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This is an entire 30 hour electrician prep course (I like 3 hours a night for 10 days). Compare with $300.00- $900.00 courses from the other guys. This ebook is broken down into 11 sections which I give as packages to my students. After each section you will be directed to take an online quiz. You have nothing to lose here guys read the testimonials below.

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Just wanted to say thank you for your book again. I passed the E2 - Commercial Electrical Inspector exam on my first try. I have to say, it did take me about four-five months to dig deep into the NEC to understand concepts and get a better feel for where things were. 

Regardless, your book was a pivotal tool for me to pass the test. I totally got right answers because I knew where to look based on what you suggested to highlight. 

I hope you continue to update this book for future test-takers.

Again, thank you!





I just wanted to reach out to let you know that I finally got around to taking my electrical exam test again. I successfully got word today that I passed. I would like you to know that without your help and the use of your study guide, ray holders, and the uglys book you suggested I pick up I made it happen. I am not sure it would have been possible unless I choose to spend a bunch of money on an in-person study session. I can honestly say that your study guide gave me the tools necessary to learn how to use the NEC book and look up the questions easier. Thanks again for putting this out there and for your help chatting with me in the past. If you are ever in the Austin, TX please look me up. Hope your family and you are doing well.


Josh McDermott-Owner

Josh’s Pool Service


Mar 2, 2017 at 8:32 PM

Message: Thanks for the practice!


Message: I have just passively went through your website here and think you have done a great job. I have studied Henry books and tapes and some of my CODE books, I am 77 years old and have been an electrician for 40 years. I've not studied the code since 2003 and am preparing to take the exam for my master license. I think this course book will be a big help. Thank you for your efforts in helping.


Message: good study guide



you are M.L. and first G.H.


Not sure if this is good or bad but Thank You!


12/28/16 at 1:25 AM

Message: Thank you very much very helpful



12/24/16 at 9:38 PM

Message: It's a long story as to why I didn't have any time to study for the Alabama electrical exam so I won't go in to that. Sadly I have hardly ever even opened a code book because I have always worked under my dad. I literally studied the material for one and a half hours a few nights before the test. I got half way in to chapter 2 readying and highlighting pretty quickly. I guess that short time really helped me understand the keywords and indexing. I passed the test with an 86% score. Thank you very much for this great resource. I am not passing this page onto my brother to help him pass his test. 

.... Phillips


Message: Very skillful and beneficial


Message: John Hoover, Exam Passed


Hell Yes!! 


10/10/16 at 6:03 PM

Message: Thank you


Squarespace <>To

10/05/16 at 3:08 PM

Message: Good work

Message: Hey Jim! 
My name is Garieth Shannon and I have just started your academy so in hopes that i can FINALLY polish my test taking skills enough to get my journeyman license. First I have to say that so far I am really enjoying your study program and look forward to the positive results. Earlier you said if there were any questions or we noticed anything to let you know so you can explain or fix them. Well, I just completed the general knowledge practice quiz and missed #5. You have the working clearance for personnel doors as 800 Amps or more. This may be a code update that I'm not aware of but my 2008 Code book (section 110.26(C)(3)) is telling me 1200 amps or more. And also regarding the chapter of study for this quiz, MY book doesn't have a 110.28 at all. 
Again, THANK YOU so much for the time you put into this! I really enjoy finally having a practice system with actual feedback on why I missed a question so I can learn from my mistakes.




10/01/16 at 2:49 PM

Message: I passed the Virginia Master Electrician Test, This site helped a lot. I didn't want to go somewhere to take a course or anything like that. I learn better on my own. I was able to do it with the help of this site and other web based resources. Thanks!



09/05/16 at 12:55 PM

Message: Thank you for all that you're doing.


Message: Hello Jim I'm pablo I hope u remember


What's up Pablo! I remember you. Let's do this.

Message: Hello Jim,
My name is Randy and I'm going to throw you a little bit of a curve ball. I have been a mechanic, electrician, plumber, manager, IT guy for 40 years. All self taught. I understand basic electricity and circuits but I have never studied any electrical books at all. Over the course of the next two to three months I plan to ace the journeyman's exam. Wish me luck.


Good Luck!



09/05/16 at 12:55 PM

Message: Thank you for all that you're doing.


Message: This is the easiest explanations to understand. Thanks



07/28/16 at 2:03 PM

Message: Awesome study guide!!! Has been a great help and I have pointed many other apprentices to it.


Message: Jim,
Great study guide. Took me through things I never looked at before. I am taking the South Dakota Electrical Contractors exam this week and although I am a licensed Master Electrician for 25 years your guide was very helpful. I hope you got paid for the ads I clicked! Thank you


I did man.. Thank you so much for clicking!

Message: Jim, thanks for your help. With the information from your site I was able to pass the KY Masters Electrician exam. While the test was difficult I felt very prepared by simply going through your guide, reading everything suggested, and highlighting the recommended sections. You have put together a great resource thanks again.


Hi Jim,

I just wanted to follow up and say thank you. I've been studying and practicing with your methods of index and key wording, and today I passed the NEC test! Thanks again!


Message: hey man, I just passed my exam! thanks so much for the help! you rock!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!


Message: Jim,

First of all I can tell you are "good people" just due to the fact that you offer up your personal time to help other sparkys study.... (and not to make a buck!!!)
I am an electrician from Northern California and got my C10 (elec contractors lic) back in 2005. I recently moved my wife and 3 kids & I to Idaho. After getting my contractors license over a decade ago I have not done any type of continued ed as its not required by contractors. As you know many of us find our niche in the trade and don't really learn about much other than what we do on a daily basis other than keep up on new codes on energy efficiency etc. As you also know the state exams cover everything and in my opinion, require some serious studying no matter who you are. I am a high school dropout who got lucky falling into the best trade out there, but do not have the study habits to be confident going into this exam.....especially being that its timed.
I took the Idaho Journeyman once a few weeks ago and failed miserably. As I searched for a prep course to help me pass I was willing to spend whatever necessary to get this behind me since I cant work and provide for my family without it. I found your site/study course and it was by far the best fit for me. Even though I would not recommend it, I only had just barely a week to use it before my "re-test" date and hit it as hard as I could. Everything I did that got me the passing score I did was from what I learned here. Even down to the little details like using the header ABOVE THE LINE at the top of the page. I never went thru a formal apprenticeship program so I never had the classroom time to learn the tips like that which help huge when it comes to speed and finding what youre looking for.
After using your guide for a week I PASSED my Idaho Journeyman today with an 83%!
I cant tell you how relieved I am, and also grateful I found your site. I will refer everyone I know to your site for preparing to take the exam.
Thank you for doing what you do brother!!!
Boise, Id 4/26/16


“Message: I haven’t taken my electrical test yet, but i wanted to say you’re awesome man its so hard to find some free help or at least a little bit. Also you’re stuff is very reasonably priced thank you ”

— Zack

I am studying for my RW, and i just wanted to thank you for making the study guide.

Thanks again,
Ethan Arquette”

“I stumbled upon your study guide a week ago looking for something that would prepare me for the real thing. Your guide has given me so much insight on what I need to focus on and what I shouldn’t “waste” my time studying. I like knowing ahead of time what to expect so I can make provisions accordingly and this allows me to do so. I will be taking my exam in August but I wanted to start my grind at the beginning of the year; which I did. I was using the Mike Holt exam prep book. It’s a nice well layed out book. However there’s too much going on in the book for study purposes. It’s just too much extra material that it’s overwhelming. I also have a set of Tom henry books that I haven’t gotten to since I first started my apprenticeship.
I wanted to let you know that I am thankful that you took the time to share your valuable experience and knowledge of the code and the electrical exams. I will definitely inform you when take it this fall and pass it.
Thanks again for you time and hard work to help electricians like me.
Sent from my iPhone”


Good morning and hope this finds you well.
I found your website a few days ago and wished I would have found it sooner.”

— Jamie

“Name: Brian Bruder

Message: Great site, let my card expire and now I need to retake test.”

“Jim at is THE reason I was able to get over the hump and pass my New Hampshire journeymans test. I had failed twice with a score in the low 60s and didn’t know where I was going wrong. After taking his practice test it showed my my weaknesses and even better, showed me how to find the correct answers. A majority of the other sites don’t do that. I have been on a ton of them and no other site helped me as much. He even called me to discuss my study habits and go over trouble areas. Jim is clearly passionate about his trade and extremely knowledgable with the NEC book. Although it doesn’t tell me my grade, I know I must have improved 20 points or more. Thank you Jim.”

— Rob Thomas

“Message: I just want to say thanks to Jim for the site and expert feed back. I just took my Texas Journeyman test and passed. I had taken the test six times already in 6 years all fails. I followed the study guide and took test option #2 and afterward Jim was able to show me how to improve in areas that needed improvement and some tricks in the code book. Jim called on his own time to make sure I was ready next day for Journeyman card!!!

— Aaron Minor

“Thanks. Journey exam passed. Nice site. Used it along with Holt. See ya!

Sent from my iPhone”

— Brian Robbins

Message: I've been a licensed master, electrical contractor and electrical sub code official in NJ 25 years contractor and 8 yrs ago took all 3 test modules for inspector TWICE ! Because I had to take them all again for Penna, well I always passed first because I always kept up with the material and I know my book well as well as all the math. Well I was hurt pretty bad and I cant work anymore but I can do administrative so I need MD,CONN,DEL,MASS and right up to Vermont for a huge communications corp. I had not been in the book for almost 7 years but still feel comfortable, what I didn't anticipate was they changed the locations and names of tables, so it took me longer to navigate, I gave myself an hour for the first 25 questions (and they were good fairly tough questions) but I actually had 75 mins, I come out with a 68% !!! lmao.... Its cool because I can tell Jim is passionate for his work as I am and trust me that flame never goes out! So I thought I could do this without the tabs but I am going to have to order them. I use three different methods of navigation, 1) Tabs 2) Glossary in the back 3) Memorizing articles. But hats off my man, I was going to do the same thing with a website called code Q-A but I don't have the patience. Jim will prep you and prep you well for those needing it, and if you don't think you need it let me tell you something right now, there is about ZERO questions of residential on the test, its all about time, navigation and applying math to all of it. I need the 2011 tabs so now I gotta go navigate the site, good luck everyone. Jim B NJ


“Message: What i liked about these test is that if you got the question wrong, not only does it show you the right answer but how to work the problem if it has to do with calculation and where to find it in the NEC book. Great job keep up the excellent work. Definetely will recommend this webpage to friends of mine.


“Message: I enjoyed the tests, they were very helpful for me drilling myself to use the book in preparation for the test. There was a good variety of questions as well. One question I would consider rephrasing is a question on test 1 regarding the minimum conductor length beyond the box. The question posed references a box 8” deep, but the code pertains to dimensions of the box openings being 8” or less not the box itself. Thanks again for the free use of the tests, the code references and explanations of the answers were great for review.


“Message: great test !!!!!! I missed a couple of easy ones, by not reading correctly, I am about to take my first test, and I am taking as many practice exams as possible. But yours is not boring like the other ones that you have to take like a month just to finish, I finish mine in one hour and forty minutes and I took a picture to remind me that with enough practice I can probably pass my test. Thank you very much.......

“Message: Thanks! I’m taking on-line quizzes to prepare for a homeowners exam at the county. Their exam doesn’t have industrial or commercial questions (or so I’m told).

“Message: Thank you!

“Message: thanks man. practice makes perfect.

“Hey man,

Thx for writing. ...i passed !!!! 78%

Your study guide really helped. Thx. Lot man. Thx a lot

Sent from my Verizon Wireless 4G LTE Smartphone

This Electrical Exam Study Guide is 94 pages long and 19196 words. This is the culmination of my own testing experience and chatting with guys just like you taking and passing the Electrical Exam.

I hope you enjoy it.

NEC® and NFPA® are registered trademarks of the NFPA. By using this website, you agree that you fully understand that is not affiliated, approved or endorsed by the NFPA. Views and opinions expressed on this website do not necessarily reflect the views of the NFPA.

© 2013-today

Electrical Exam Study Guide

Your helpful study guide, tips and tricks for passing the NEC® Electrical Exam. Learn easily and fast everything you need to know about your Master, Journeyman, Contractor, and Residential Wireman electrician test.

Know your bulletin

The electrical exam testing facilities are currently using the 2008, 2011 and 2014 NEC book, depending on what State you're in. The first thing you need to do is carefully read the entire bulletin and find the breakdown of the test you will be taking. The reference material you are allowed to bring into the electrical exam should be listed. This will ensure you that you are studying the right thing. Several times I have had guys call me and say they failed because what they were studying wasn’t on their exam. So it’s important to find out.

Here is an example of an exam bulletin: You see here the reference materials listed. You can expect some questions from all materials listed, but the majority will be from the code book.


Sample electrical exam bulletin

Look at this Bulletin. Every electrical exam in 50 States has questions from these content areas. Notice the difference between the Master and Journeyman is just the amount of questions and some planning. Some bulletins will have state and local laws written at the end which must be studied. The bulletin for your state will tell you exactly what needs to be studied. Go to Lesson 2 and get your electrical exam bulletin

How to use this study guide

1.    If you see an article number read that article

2.    If you see index: find that word in the index, study the list, then go to the article.

3.    If you see highlight, read the article and highlight the word or article because it could be a question on your exam. Don’t over highlight! Only highlight after you understand why.

4.    Call your testing facility to make sure they allow highlighted material in your NEC Book first. Or review your test site regulations. Example of regulations click here.

Grab your book and let's begin.

Let me show you how to break down your bulletin, by studying this bulletin. Look at the Journeyman section of this bulletin.

Note: If you have your bulletin get it out and follow along. Use your code book. All of these articles will be on your electrical exam.

·        8% General Knowledge. Index General Requirements for wiring methods. Article 300 I see at least 8 exam questions just reading this index. Example: What is the minimum free conductor length outside a junction box? 

·        13% Services and Service equipment. Look in your index at these two words. Read the column of articles. You are basically looking at the answers to 13 questions from article 230 and 230-V.

·        3% Feeders. Index: feeders, look for Motors 430-II. You have 3 questions on feeders and Motors will definitely be one. Go to article 430. I just want to show you something quickly. You see figure 430.1 look at Part II. 430 is a very long article and this is how you find section II. 430.21 Through 430.29 your answer will be here. Go back to feeders in the index and read it.

·        20% Branch Circuit and Conductors. 20 questions here. Let's look up Branch Circuits in the indexArticle 210 & 220. Read and study the index here. Branch circuit questions can be very easy and very hard, you will have both. Take your time and carefully read each article and section in the index just to start to get used to them. Example: Index: Conductors, here we have multiple articles, and a long index but conductor questions are very specific.

·        26% Wiring Methods and Materials. Index: Wiring methods. Articles 110.8, 300, Hazardous Locations, 517, 550, temp wiring, and 520. Lots of good stuff to cover here but not a very long index. We will be studying potential exam questions for wiring methods in the main part of the study guide.

·        13% Equipment and Devices. Let's take a look at the definition of equipment in Article 100. Equipment and device questions on your electrical exam will be specific. Equipment and device answers will be found in the index directly from the question. Example: Insulation shall not be closer than ________ inches away from non- IC rated recessed luminaries.

·        3% Control devices. Take a look at the definition for Controller. Control devices are switches. Controllers turn the power on and off. It could be a simple snap switch or a programmable logic controller. Example: What is the maximum current allowed on a 20 amp snap switch?

·        8% Motors and generators. My favorite. Everybody misses motor questions. Here's why. Even if you wire 3 phase motors all day long you’re not the one who engineers the hook up. There's too much information to write here but will get into it. You will be able to quickly answer motor questions correctly. Index Article 430

·        11% Special occupancy, and Hazardous location conditions are case by case. Usually you just index the key word and go directly to a short article which gives you a word for word answer. The trick here is you must read and answer the question carefully. Example Answer: Class 1 Division 2, Class 1 Division 1, Class 2 Division 1

If you have any question at all or need help finding your bulletin, please contact my personal Email:

Now that you see the kind of electrical exam you are about to take, let's get into the Articles and Sections the of the code book that your exam questions come from.


Chapter 1

Getting comfortable with your code book

Please open your National Electrical Code® Book or NFPA 70® to the Table of Contents.

Table of Contents

There is a lot of information here and some guys pass the test just by using the table of contents. I was not one of these guys, but if you know the Table of Contents like the back of your hand it would be very quick for example to find Type FCC and Type MC Cable articles when needed.


Definitions are found two places.

1.     Article 100

2.     The section just after any main article designated with .2 like article 330.2

Take a minute now to look at some .2 articles. Like 547.2

The NEC from 2008 to 2014 has been moving definitions that will only be found in that specific article to the .2 of that article. Definitions that are used in more than one section of the code book will be in article 100.

Example: Look at Continuous Duty in Article 100. Continuous Duty is widespread all over the code book so it will be found in article 100.

Highlight: Duty, Continuous Load and Location in Article 100. 

Requirements for electrical installations


Article 110.14(C) (1) - Electrical Connections/ Temperature Limitations

I can't tell you the difference this article makes on your conductor ampacity calculations. This is the article that says you must use the 60° column in Table 310.15(B)(16) for circuits rated less than 100 amps and the 75° column for circuits rated over 100 amps.

When answering exam questions like what is the minimum size (gauge) conductor to feed a 5 HP motor. You have to look at Table 310.15(B)(16), and ask yourself, is this conductor going to be over 100 Amps or under 100 Amps? Then use the 75° column for over and 60° column for under.

Now you’re saying the 60° column is only for Type TW and UF wire. It doesn't matter. Even if you’re using THHN your terminations are considered 60° unless the question tells you specifically the termination is 75° or the circuit is over 100 amps.

Highlight: You can highlight the whole thing this article is very hard to find quickly if you've forgotten where you saw it.

High-leg marking.

Standard exam question. Answer is orange. There may be some long drawn out question but the answer is still orange.

Index: Identification, high-leg.

Highlight 110.15 High-leg Marking, orange

Working Spaces

Index: Working space, about electrical equipment, 110.26

This table 110.26(A)(1) is all about the "condition" notes below. I haven't heard of any 150 volt and below questions here. They want to see if you can determine the correct condition for higher voltages.

1.     Exposed live parts on one side of the working space.

2.     Exposed live parts on one side and grounded parts or walls on the other.

3.     Exposed live parts on both sides.

The trick here is to visualize you're standing in front of a panel with exposed live parts what is behind you.

Highlight: Table 110.26(A)(1), Condition 1, condition 2, condition 3

110.26(C)(3) Personnel Doors

Highlight: 800 A, listed panic hardware

Table 110.28 Enclosure selection

If an exam question references enclosures the answer is most certainly on the indoor or outdoor table. This is easily found in the index under enclosures.

Go to your Index and look up Enclosure. Find types, 110.28

Note: In the index of the 2014 NEC it has listed article 110.29, it's really 110.28

It’s a good idea to understand Table 110.31 “Minimum Distance from fence to Live Parts” as well.

Highlight: Table 110.31, Fence to Live Parts

Most of the questions I've heard of are on these tables but this article is full of information we use on a daily basis like Height of working space and the exceptions. Don't miss the chance to at least read the next three pages.

How was chapter 1? Let's discuss it email me at 

I want some feedback tell me how this book is helping or not helping Please let me know I’m
— Jim Smith

Chapter 2

200 Articles and Exercise’s

Articles and sections in the 200’s host the most possible electrical exam questions of any chapter. We will be covering Service load calculations, Grounding and Bonding, Branch circuits, Ground fault protection, Arc Fault Protection, and many of the possible exam questions that can come from chapter 2.

Index: Identification, Grounded conductors, Article 200

Let’s start with Article 200.6 Means of Identifying Grounded Conductors

Highlight: Size 6 AWG or Smaller and Continuous white or gray.

I think we can all agree that the neutral is either white or gray. White commonly being a low voltage (120, 208, 240) neutral and grey being a high voltage (277, 480) neutral.

If you are using white for high voltage, please group it with its conductors. 

Note: in NEC 2014 Grounded conductors shall be grouped with their ungrounded conductors by marking or cable ties.

SPEED NOTE: When finding words in the index, and articles in the code book, use the header, the sample word or number at the top of the page above the line. Don't use the middle of the page.

Branch Circuits


  • · · 210.5(C) Ungrounded Conductors

  • · · 210.8 GFCI for personnel

  • · · 210.8 Exception to (3)

  • · · 210.8(B)

  • · · 210.8(B)(5)

  • · · 210.11 (A) and(B)and(C) Branch Circuit Required

  • · · 210.12 Arc Fault Combo Protection

  • · · 210.19(A) (1) Non- Continuous Loads + 125 percent Continuous.

  • · · 210.20(A) Non- Continuous Loads + 125 percent Continuous.

  • · · 210.21(A) and (B) Outlet devices

  • · · 210.23 Permissible Loads

  • · · Table 210.24 Heavy Duty

  • · · 210.52 Dwelling unit receptacles

  • · · 210.62 Store Window receptacles

  • · · 210.63 Heating and refrigeration receptacles

  • · · 210.70 Lighting Outlets required

So basically the whole Article 210. Not to worry though. You don't have to memorize the whole thing. We are finding the key words in the index first so that it will lead us to the correct Article and the word for word answer.


Find all articles listed above in the index. Hint: Use the key word.

Highlight; Conductor in the index

Identification of ungrounded conductors

When is it necessary to identify the ungrounded conductor?

What is an approved means to identify the ungrounded conductor?

Index: Identification, Ungrounded, 210.5(C) 

When you have more than one nominal voltage in a building you must make the phase or line of the branch circuit known at every j-box and termination. Phase means color (black, red, and blue) and line means L1, L2, or L3, mark each conductor either with the line or with the phase at every j-box and termination along the way.

Highlight: Phase or Line

NOTE: You can also get here by indexing color code, Branch circuits. Article 210.5

Index: Color Code, notice: grounding, grounded, ungrounded conductors and their sections.

Ground fault for personnel

When you read section 210.8 you find two things A. Dwelling units and B. other than dwelling units. The section is not big yet it carries a lot of weight. Every GFCI on the planet has been put there because of this code article, 210.8. If you have a GFCI question in front of you definitely start with 210.8.

Article 210.8 A through C is referenced in the index 28 times. Let’s study by doing some example questions.

Example 1: Can a GFCI be placed behind a vending machine?

Index: Ground-fault circuit-interrupters. Receptacles 210.8

Highlight: Receptacles in the index

Read 210.8

Highlight: Shall be installed in a readily accessible location. Note: 2008 code does not have this change

Another place you can find this article in the index is Accessible, Ground-fault circuit-interrupters. You see these sections of code are located in more than one location in the index.

Example 2: True or false? Only countertop surfaces with 125 volt, 15 and 20 amp outlets in the kitchen of a single family dwelling shall be GFCI protected?

Index: GFCI, Receptacles, Kitchens

Index: Kitchens, Receptacles in

Read article 201.8(A)(6) and Highlight: Kitchens, Countertop surfaces,

The answer would be True.

Example 3: Other than dwelling units within how many feet from the outside edge of a sink is GFCI protection required?

Index: GFCI. Receptacles, 210.8

Here is an example where the exact answer is not in the index. You just have to use the keyword they give you “GFCI” and go to the article and drill down.

NOTE: Dwelling units and Other than Dwelling units require GFCI protection within 6' of a sink.

Highlight: Sink and 6'

Branch Circuits Required

Will keep the same format here and show you some very easy example questions. Try and find the key words here in your index without looking at the answer.

Example 1: In a Dwelling Unit how many small appliance branch circuits shall be provided?

Index: Branch Circuit. Small appliance.

Answer read 210.11(C)(1)

Highlight: two or more 20 amp

Example 2: In a Dwelling Unit how many Laundry branch circuits shall be provided?

Index: Laundry, Outlets, Dwelling. While you are here please look at the additional articles in the index for Laundry. Outlets. Dwelling

Answer 210.11(C)(2)

Highlight: one additional 20 amp circuit

Note: This is not the outlet for the washing machine or dryer this is a circuit just for the general purpose in the room.

Example 3: In a Dwelling Unit how many Bathroom circuits shall be provided?

Index: Branch circuits. Bathrooms.

Answer 210.11(C)(3)

Highlight: One 20 amp branch circuit

These three questions are the basis for Service Feeder load calculations on dwelling units. Article 210.11 (C) is the explanation for how we get the first part of general load, for dwelling units. The code states these circuits shall be included in a dwelling unit therefore must be accounted for in the Service Feeder Load Calculations. Minimum. 

We will get into load calculations but not here.

Arc-Fault Circuit-Interrupter Protection


Electrical Exam Academy arc fault


2014 code book

Index: Dwellings or Arc-fault circuit interrupter

Those of you taking the NEC 2008 test can delete Kitchens and Laundry rooms to this floor plan.

Either way if you get a location question for Arc-Fault just look it up in the index under Arc-Fault Protection or dwelling and read carefully.

Note: 210.12 Exception #2 is a device that looks like a GFCI and can be installed at the first outlet location. This will protect the remaining portion of the branch circuit.

Highlight: Kitchens and Laundry

If you have not paid for this exam prep CLICK HERE.

Thank You,


Branch-Circuit Ratings

Index: Branch circuit. Conductors

Read sections 210.19(A)(1) and 210.20(A). 

Highlight: Continuous loads, 125 percent

For testing purposes you will need to rely on the exam question to tell you what is the non-continuous load and what is the continuous load. 

Non-continuous Load + (Continuous Load x 1.25) = Branch Conductor Size

Continuous load x 1.25 = Branch Conductor Size

210.19(A)(3) Household Ranges

Index: Ranges. Branch circuits

Notice all places in the code book where you can find sections on ranges.

Read section 210.19(A)(3)

Highlight: 8 ¾ KW, Minimum Branch-Circuit Rating, 40 Amperes

·        ·        Note: Hopefully by now you are starting to pick up some speed using your index. If not let's pick it up a little. When you see index, get to the keyword quickly. Use the header of the index to find your key word instead of the middle of the page.

·        ·        For now, just get to the keyword quickly, then slow down and take in the whole index column for that keyword and feel free to look around a bit. Then once you’ve studied a bit of the index find the article quickly again using the header.

·        ·        Also you can see they’re times when you index the article like Branch Circuit and times when you index the keyword like Range.

210.23 Permissible Loads

Index: Branch circuit. Requirements.

I want you to read article 210.23 first so we can nail down what we're talking about with permissible loads.

·        If you have a circuit that is not dedicated, but feeds equipment. That equipment can only use a percentage of the ampacity, the circuit is rated for. Circuit ratings 15, 20, 30, 40 or 50 amps

·        The question is going to be what percentage a piece of equipment can take from a branch circuit.

·        The key will be to find 50%, or 80%.

How do we find it? Answer, you don't. Permissible loads are very hard to find in a testing environment.

·        You can index branch circuits but you will have to remember you're looking for an appliance. You can index Utilization equipment but you will have to remember Permissible loads. Either way it only gets you to section 210.23. So highlighting and drilling down into the section will be important here.

210.23(A)(2) Utilization Equipment

If you have a piece of equipment fastened in place being supplied by a branch circuit that supplies two or more outlets, the equipment shall not exceed 50% of the circuit rating.

Example: What is the minimum size branch circuit for 3- 20 amp receptacles and a 9.5 amp appliance fastened in place? Answer 20 amp circuit

9.5 amps is less than 50% of 20 amps.

Index: Branch circuits. Appliance

Highlight: 50 Percent

210.23(B) 30 Amp Branch Circuit

If you have a piece of equipment that is cord and plug connected to a circuit supplying two or more outlets, it shall not exceed 80% of the 30 amp branch circuit.

Highlight: 80 Percent

Let's look at the Summary of Branch-Circuit Requirements Table 210.24.

What type lamp holder can be used for a 30 Amp Branch Circuit?

Index: Heavy-duty Lamp holder

Answer: Table 210.24 30 A column, Lampholders permitted, Heavy Duty

Highlight: Heavy Duty

This is why when you purchase HID lighting the Fixtures come with the Mogul Base that is Heavy Duty. This is the article that tells Lighting Companies what style shall be used.

There is plenty of discussion about what is considered "Heavy Duty Lampholders" but for testing purposes let’s keep it simple.

Dwelling Unit Receptacle Outlets

Read section 210.52 complete

What can I say here? This is our job guys. You have to know where you’re going to install receptacles to code in dwelling units. If you are taking your RW (Residential Wireman) then this section is all you. Read it, know it, Love it.

This article is referenced 19 times in the index.

You probably won't be lucky enough to get easy questions like the ones from this section but if you do, the question will reference some location, like- Kitchen sink, wall space, counter top spaces, or outdoor outlets.

Index: dwellings, Receptacle outlets required

Highlight: in your index, Receptacle outlets required 210.52 and Protection by ground-fault circuit-interrupters 210.8(A)

Return to section 210.52 and highlight:

·       210.52 Dwelling unit receptacles

·       210.52(4) 5 ½ ft.

·       210.52(A)(1) Spacing, 6 ft.

·       210.52(C)(1) Wall Countertop Spaces, 12 in., - 24 in.

·       210.52(C)(5) not more than 20 in above countertop

·       210.52(E) Outdoor Outlets

·       210.52(E)(1) 6 1/2 ft. above grade

Now let me explain a little bit. Say you are laying out a house with required wall outlets every 12’ or not more than 6 ft. from an outlet measured horizontally along the floor. You come to a spot where you have an outlet for a TV but it is 6 ½ ft. above the floor. You cannot count this outlet in the required wall outlets since it is over 5 ½ ft. off the floor.

Now for the kitchen lay out. Where you have countertops over 12 inches wide you need an outlet. Where you have long countertops you need one within 24 inches from beginning then not more than 2 ft. from an outlet measured horizontally along the wall and within two feet from the other end. You have to make this work even if you’re an inch off.

Example questions:

 You have a 4 ft. counter with a 2 ft. range in the middle of it. How many outlets are required? The answer is 2 because you have 12 inches of counter on each side.

You have a counter that is 8’ long. What is the minimum amount of outlets required? The answer is 2. You place an outlet exactly 24 inches from each end with exactly 4 ft. between them. You are always within 24 inches of an outlet and within 24 inches of each end.

You have a countertop that is 8’6’’ long. What is the minimum amount of outlets required? Answer 3. Now even if you have the max distance of 24’’ from the end of the countertop, you would have more than 4’ between the end receptacles. Therefore, at some point along the wall you are going to be more than 24’’ from a receptacle.

 If you have an outlet more than 20 inches above the countertop it doesn’t count.

Outdoor outlets are required on a dwelling in the front and on the back of a house. If that outlet is more than 6 ½ feet, it doesn’t count.

2014 NEC: One interesting change to balconies. The exterior receptacle must only be accessible from the balcony it does not require it to be over the deck. This is for the "New York Deck" which is a door that opens to a railing with no real deck maybe 6'' deep and tight to the door on each side. 210.52(E)(3)

Show Windows

This is a good question. How many outlets installed within 18'' from the top of a show window will code require for 30’ of show window?

Index: Show Windows, Receptacles 

210.62 Show windows

Every 12 linear foot or major fraction (amount greater than ½) thereof shall have an outlet. So 30 / 12 = 2.5 Answer 2

Highlight: 12 linear ft.

Heating, Air-Conditioning, and Refrigeration Equipment outlet.

Example question. Within how many feet of heating equipment shall a receptacle be required?

Index: Heating equipment. Receptacles 210.63

Answer: 25'

Highlight: 25'

Have you ever wondered why you need an outlet next to the furnace? This piece of code is the reason.

This answer can be tricky to find in a hurry. It is in the index under air-conditioning, outlets, and Heating equipment, receptacle outlets.

Lighting Outlets Required

Example question. In an attached garage you have a stair case that has 7 risers leading from the garage floor to the entrance of the house. What is the minimum number of switches required for these stairs?

Index: Lighting outlets. 210.70

Read 210.70

Answer: 2

If your stairs have more than 6 risers, then you are required to have a switch at the top and the bottom or each floor level.

Highlight: 6 risers or more

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Short and sweet. Only one article of value for testing purposes.

Index: Feeders, Ground-fault circuit-protection

We really want section 215.10 here but it’s close enough to drill down.

215.10 Ground-fault protection of Equipment

Highlight: 1000 Amperes, Wye

There are plenty of feeder questions on the exam but we get those answers from the target articles.

NOTE: The conductor ampacity Table 310.16 will be called Table 310.15(B)(16). For those of you studying the 2008 code.

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Branch-Circuit, Feeder, and Service Calculations


For starters just read article 220.

These 10 pages of articles and calculations should be memorized. Memorized might be too strong of word. Just read Article 220 over, make note of the tables and other interesting articles, then when we do the example load calculations you’ll know what and where to refer back to.

Index: Branch circuits. Calculation of loads

Index: Feeder. Calculation of loads

Index: Service. Calculation of loads

Index: Loads.

Note: I see 14 exam questions in the loads index. Nearly all of the items under loads get used on exams. Some are easy and some are time consuming.

Flow chart

·       Load calculations lead to feeder sizes.

·       Feeder sizes lead to equipment and device sizes.

·       Using table 310.15(B)(16) we find the correct size AWG or Kcmil of conductor.

Using table 310.15(B)(16) sometimes requires adjustment factors. The adjustment factors are “over 3 current carrying conductors in a raceway or cable” and “temperature”.

 How many wires other than grounds are in the conduit? If the answer is over 3 you must derate the current carrying capacity of each conductor by the percentage in Table 310.15(B)(3)(a)

What is the ambient temperature? Table 310.15(16)(B) is based on 86° F. If the temperature is greater than 86° or less than 78° you will use Table 310.15(B)(2)(a) and apply the correction factor.

Example question. Conductors are feeding a fan inside a warehouse with an ambient temperature rating of 105°. The fan draws 16.7 amps of current and has terminations rated at 75°C what is the minimum size conductors allowable for this location.

Branch circuit conductors suppling continuous loads or single motors shall be sized 125%

16.7 x 1.25 = 20.875 or 21 Amps

12 AWG wire from Table 310.15(B)(16) in the 75°C column is rated for 25 amps

25 amps x .82 (the correction factor from Table 310.15(B)(2)(a) for 105° ambient temperature) equals 20.5 amps or 21 Amps so you can use #12 conductors for this application.


Index: Calculations

You will see here Annex D; see also Loads

Go to the back of the book and read Annex D. Start from the first 5 paragraphs. If you have never done load calculations before this is going to look crazy but just like everything else in the book when you take it step by step and learn where to find each part of the calculation, it turns out to be simple addition.

Its finding out what to add up is the hard part and takes some practice.

Most importantly read the questions in Annex D. These are exactly the kind of questions you will have on your electrical exam.

You typically don't see any answers with fractions of an Ampere. Round up or down. Per Annex D 3rd paragraph Fractions of an Ampere.

Index: Loads, service Article 220

Notice the location of the Demand tables for ovens and dryers.

Branch-Circuit Load Calculations

General Lighting Loads for Specified Occupancies

The beginning of Service Load Calculations is finding all your Branch Circuit Loads. We need to take a second here and read Article 220 Part III section 220.40. It says the Feeder or Service shall not be less than the total calculated load from the branch circuits.

In this section we will discover all the Branch-Circuit loads. So we can determine the correct size Service Feeders

First thing you do is find the General Lighting Load in table 220.12.

To do this we need to determine the square footage of the occupancy from the exam question.

Read section 220.12

Highlight Section 220.12, calculated from the outside dimension, and shall not include spaces not adaptable for future use.

Example. What is the calculated lighting load for a Single Family Dwelling Unit that is 3500 square feet with an unfinished basement of 2000 square feet and a 400 square foot Garage? Answer 3500 x 3 = 10,500 VA

Go to Table 220.12 and look for Dwelling units.

Highlight note (a) at the bottom of Table 220.12.

Read section 220.14(J). Highlight the outlets specified in (J)(1), (J)(2), and (J)(3) are included in the general lighting load of Table 220.12

These outlets are included in Table 220.12

·       All general use receptacles

·       Required outdoor receptacles

·       Garage and basement receptacles

·       All required lighting outlets from section 210.70 (A) and (B)

Remember this is all leading to the proper size conductors and service equipment to feed the dwelling.

So all these Branch-Circuits are covered for dwellings.

The only required circuits we are missing now is the:

·       Small Appliance load section 220.52(A)

·       Laundry load section 220.52(B)

·       Range

·       Dryer (optional)

Here we need to get through Other Loads All Occupancies to get back to our residential load calculation.

Other loads

If you are meant to calculate the load from a set of drawings either resi or commercial like “in the real world”. You will need this section because it provides the Volt-amps of outlets like signs, show windows, and receptacles for calculating other branch circuits off a set of prints.

99% of the time we are just dealing with a question that lays out all of the information.

Follow along in section 220.14(A) – (L)

Highlight just the numbers from

1.    Appliances based on the ampere rating of load served

2.    Electric Dryers and cooking appliances Tables 220.54-220.55

3.    Motors

4.    Luminaries

5.    Heavy- Duty 600 VA

6.    Signs 1200 VA

7.    Show windows 200 VA per foot

8.    Fixed multi-outlet assemblies, unlikely, 5’, 180 Volt-Amps

9.    Fixed multi-outlet assemblies, likely, 1’, 180 Volt-Amps

10. Receptacles 180 volt-amps, 90 volt-amps

11. Banks and office buildings

Now let’s find these things in the index and review.

Sign and Outline Lighting

When calculating loads for a commercial building you will be required to have a number of signage circuits as described in section 600.5(A).

Read 600.5(A)

Index: Signs, Branch circuits 220.14(F)

Highlight: 1200 VA in article 220.14(F)

Fixed Multioutlet Assemblies

Index: Multioutlet assembly

Highlight: 220.14(H) unlikely (5 ft.) and likely (1 ft.)

Receptacles Outlets

Index Receptacles. Outlets, loads 220.14 (I)

Highlight: 180 volt-amperes

Banks and Office Buildings

Note: look at the Table 220.12 at the very bottom you see this note b.

Highlight: 1 VA / ft.

Feeder and Service Load Calculations

Now that we have the branch circuits let’s get back to residential load calculations.

Read 220.40 General

Highlight: after any applicable demand factors

Small-Appliance and laundry loads for the dwelling calculation.

We have to go back a little to find the code for Small appliances. The one that says we need two small appliance circuits minimum and one laundry circuit.

Read: section 210.11(C)(1) and (2)

Now look at the bottom of section 220.52(A) and (B).

Highlight: These loads shall be permitted to be subjected to the demand factors of the general lighting circuit.

So this is why in the example load calculations you will see these two items (small appliance circuits and laundry circuit) being adjusted by the lighting load demand factor of Table 220.42.

100% of the first 3000VA and 35% of the portion remaining.

Highlight: 1500 volt-amperes for each 2 wire.

For load calculations if you have more than 2 small appliance circuits each additional circuit will be calculated at 1500 VA.

Highlight Table 220.42 Lighting load demand factor

So the first part of any Service Feeder Load Calculation will require you to use Table 220.42 and find the general load as described above, next we will discuss the rest of the calculation

Electric Clothes Dryers

Electric Clothes dryers are optional but they will usually have a multiple dryer scenario to test you on the Table 220.54

For a single dwelling unit, you must be aware that dryers are calculated at 5000 watts (volt-amperes) or nameplate rating whichever is more. If you have between 1-4 dryers, they will be calculated at 100%

Read section 220.54

Highlight: shall be ether 5000 watts

Index: Tables. Household clothes dryer, Household ranges

Every Dwelling will have a range circuit.

Read Section 220.55

You will see that each range, wall mounted ovens and cooking appliances are calculated from Table 220.55.

Carefully read Table 220.55 and understand all the notes at the bottom.

Looking at Table 220.55 notice that Column C is to be used in all cases and column C is not a percentage it is a KW rating. So any oven or cooking appliance rated up to 12KW for a single device will be 8000 watts or (volt-amps) for calculating service feeders. For two devices it will be 11KW and so on.

For cooking appliances with a rating over 12KW you will use Note#1 in table 220.55 which says for every KW over 12KW you will increase the max value in the table by 5%.

Example: What is the demand factor for 1 – 15KW oven.

15000 KW – 12000 KW = 3000 KW

5% for every KW over = 3 x .05 = .15

8000 is the maximum demand so 8000 x .15 = 1200

1200VA + 8000 VA = 9200 volt-amps which will be allowed for a 15 KW oven.

You will be tested on your ability to use the demand factor tables 220.54, 220.55, and 220.56. It is simply the fact of electrical wiring that not all loads will be on at the same time.

The code book allows us to reduce the size of the Service Feeders so that every Multi-family dwelling does not require a 400 amp Service.

So in summary of Single Family Dwelling load calculation look at D1(a) in Annex D. When you look at this example, keep in mind this is a very basic house that does not have heating or AC. It does however have the minimum required loads that every house shall have.

Example: D1(b)

If the question has some extra branch circuit connected devices, they will give you the voltage and amperage. You will add these small loads to your basic load calculation using a chart keeping the loads balanced across line 1 and line 2. Example D1(b).

Note that if you just added all the other loads in example D1(b) to one line or phase you would have 117 Amps on Line A and 78 Amps on Line B 

If the question has Heating or Air conditioning amperage you will be using Example D2(a), D2(b), or D2(c). For the Dwelling Unit.

Study: Example D2 the first thing you need to find is the biggest load on the service. Is it the Heat or the AC? You’re not going to be running the Heat and the AC at the same time so you will only calculate the KVA for the largest (Heating or AC) load @40%, plus 100% of the first 10,000 KVA and 40% of the remaining load. This is the total load.

To see an example exam question please click here.

Kitchen Equipment

Index: Kitchen Equipment, Section 220.56

Attention Masters and Contractors it is common to have a commercial kitchen equipment question on your exam asking for the correct size service feeder for a kitchen panel. They will give you a list of all the equipment. Use the demand factors from Table 220.56.

Part V. Farm Load Calculations

Index: Farm building, feeder calculations, 220.103 total load.

When calculating a farm load use Table 220.103

I have never seen or heard of any other exam questions except on the Table 220.103. If you do please reach out to me so I can include your knowledge.

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Jim Smith

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Outside Branch Circuits and Feeders


Conductor size and Support

Read 225.1 I think it’s important to read the scope of this article so you can relate keywords to it.

Highlight outside branch circuits run between building or on buildings.

Index: Conductors. Outside wiring, 225.6

Index: Outside branch circuits and feeders

There are a couple of good questions here. Sizes for 50' spans and above. Pay close attention to above 600 volts and 600 volts or less.


(A) Overhead Spans

(B) Festoon Lighting

Both articles are easily found in your index. Both questions will be looking for minimum gauge wire.

These articles for Branch Circuits are the same as for Overhead Service-Drop Conductors.

·       225.16 Attachment to Buildings

·       225.18 Clearance for Overhead Conductors

·       225.19 Clearances from Building for Conductors not over 600 Volts, Nominal

You will most likely see the Clearance Questions- like "Over roads subject to truck traffic" or "Over sidewalks" in the Service-Drop article not the outside branch circuits.

I have highlighted in my books 225.18 Clearance but more in the Service-Drop Section.

Quickly Read Articles

·       225.30 Number of Supplies- only one per building

·       225.33 Maximum Number of Disconnects- 6 switch rule

·       225.34 Grouping of Disconnects- group your disconnects

·       225.36 Suitable for Service Equipment- Check the UL listing or fail your inspection

·       225.37 Identification- Plaque or Directory

Again the rest of Article 225 is all very important but we will be going over all of these points in Article 230.

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Article 230 Services

GO TO article 100 Definitions and read.

·        Service:

·        Service Cable:

·        Service Conductors:

·        Service Conductors, Overhead

·        Service Conductors, Underground

·        Service Drop:

·        Service-Entrance Conductors, Overhead System

·        Service-Entrance Conductors, Underground System

·        Service Equipment

·        Service Lateral

·        Service Point


·        Service cable

·        Service conductors

·        Service drop

·        Service-entrance cable

·        Service-entrance conductors

·        Service-entrance equipment

·        Service equipment

·        Service loads, calculations

Imagine looking at the transformer that feeds your house. That transformer is taking some voltage like 13,800 Volts and transforming it to 240 Volts. 

The conductors that run from the transformer to the first disconnecting means are the Service Conductors.

If these service conductors are over-head they are called the Service Drop.

If these service conductors are underground, they are called the Service Lateral.

Service Cable "type SE" or "service entrance" rated cable is used from the Service Point to the premise wiring. SEU has a bare concentric neutral, and SER has a jacketed neutral and a bare equipment ground.

Service Entrance Conductors are the conductors from the Weather Head to the Meter Socket and the conductors from the Meter Socket to the Service Equipment.

Service Equipment = Disconnect and/or Panel

During your exam you will only be asked to determine the size of the conductors from the Service Point to the Service Equipment.

Service Point = Weather Head or Meter Socket

Now that we have the definitions of the Service let’s look at Figure 230.1. Here is a diagram of all the Parts in Article 230. Mostly you be finding the answers from the keyword in the index but knowing the parts of Article 230 can’t hurt.

How many services can run to a building or other structure?

Index: Services, number, 230.2

Highlight: Services in your index.

The answer is one. There are exceptions but unless the building is crazy large or the other service supplies a fire pump the answer is one.

230.9 Clearances on buildings.

Guess what? You should not be able to reach out and touch the service conductors. You should not be able to hit the Service drop with your truck either.

We need clearances to tell us exactly how high the Service Drop should be.

If you have a window that opens, or a deck, door, ladder or any structure you are expected to stand on your Service Drop can't come within 3' of it.

Highlight: 3'

Part II Overhead Service Conductors

Index: Overhead service conductors

Highlight: In your index, Minimum size, and clearances.

 Read 230.23 Size and Rating

Highlight: 8 AWG copper and 6 AWG aluminum

Index: Clearances. Conductors, Overhead services

Section 230.24(A) tells us 8' above the roof for a distance not less than 3' from the edge. So if your Mast is on the gable end you can fly in over the eve if it's not more than 3' feet from the edge of the roof.

Highlight 8’ and 3’

Vertical Clearances for Service-Drop conductors.

Index: Clearances, Conductors, overhead service

Highlight and Read section 230.24(B) carefully. Minimum clearance from final grade.

·        10 ft. Voltage does not exceed 150 Volts to ground, accessible only to pedestrians on residential property

·        12 ft. Voltage does not exceed 300 Volts to ground, over residential property, residential driveways and commercial areas with no truck traffic.

·        15 ft. Voltage exceeds 300 Volts to ground, over residential property, residential driveways and commercial areas with no truck traffic

·        18 ft. Any voltage above truck traffic areas such as public streets. Roads subject to trucks and other land such as cultivation, grazing, forest, and orchard

What we are talking about here is where the service drop fly’s over the yard, sidewalk or driveway and connects to the building. You need to have a minimum clearance between the ground and the lowest part of the service conductors. You must have enough height on your service mast so the drip loop has the minimum clearance as well.

Note: The Drip Loop is a loop of wire before entering the weather head or (goose neck) on a building. You want a loop hanging down in front so the rain runs off the conductors. This prevents water from running down the wires directly into the service equipment. The service Head shall be located above the point of attachment to the building.

That said for different voltages you need different heights. It makes sense that the higher the voltage the more clearance you will need.

The trick here is to read the question carefully. They will mix up all different scenarios. All in all, though this should be an easy win.

Highlight: The distances and the voltages in section 230.24.

Service Equipment -Disconnecting Means

Index: Disconnecting means, Service equipment

Read Part VI article 230

All service entrance conductors shall have a disconnect at the point of entrance outside the building or the nearest location inside the building.

Highlight: Article 230.70(A)(1), Readily Accessible Location

You can't run overhead SE (service entrance) conductors through the building and put the disconnect in the bathroom. Just bring the SE conductors into a disconnect on the outside, or into the main breaker of a panel directly inside and label it SERVICE DISCONNECT.

Highlight: not more than six sets of disconnects

If you are feeding more than one disconnect with your Service conductors. Let me start over. Say your Service Entrance conductors come directly into a meter.

How many disconnects can you tap off that meter? 

Can service disconnects be scattered all over the property? No

First the number is SIX. This is the six switch rule section 230.71. Second they have to be right there all together. If this building is on fire the men putting it out would like to shut off the power to all conductors inside the building at the same place. Except for the power to the fire pump which can be remote.

Note: if you needed more disconnects in this scenario you would have one main service disconnect to shut off the power to all conductors inside the building.

Occupants, in a multiple-occupancy building, Occupants shall have access to their service disconnect.

There is a number of safety reasons for this. Imagine the basement is flooding and you can see the heat-tape light on under the water. The service electrician will want to turn off just that tenants power while the leak is repaired. 

Highlight: 230.72(C) Access to Occupants

VII Service Equipment-Overcurrent protection

Ground-Fault Protection of Equipment

Index: Ground-fault protection. Service disconnecting means, 230.95

Highlight: wye and 1000 amperes.

Why? I don't know but I have seen this question on every test I have taken and it's really hard to find quickly.

If you have a 1000 amp or greater breaker it shall be Ground Fault Protected.

Read 230.95(A)

Highlight: The setting on that 1000 amp GFCI Breaker will be set at 1200 amperes

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Overcurrent Protection


I would be interested to know if anyone has seen questions on articles 240 through 240.6. Email me at

I have not but you would think that there is at least one question here. Look at 240.4(D) there is a lot of definite answers here but they are all kind of answered by Table 310.15(B)(16).

This is a great section to memorize anyway at least for estimating.

Index Overcurrent protection, current limiting, definition, 240.2

Read the definitions.

Standard Ampere Rating

Index: Come up with a keyword and try to find article 240.6. How long did it take you? Did you try and find Standard Ampere Rating?

Index: Circuit Breakers. Rating, Fixed-trip circuit breakers 240.6(A)

Highlight: Rating in your index

Highlight: 240.6 Standard Ampere Ratings

This article has several different questions linked to it.

When it comes to Overcurrent Protection we use standard size breakers. We protect the load conductors from bursting into flames.

You don't care that the load calculation says you are only going to need 16 amps, you still have to use 20 amp wire and a 20 amp breaker.

It's the same if you have an 821 amp load calculation for your multi-family dwelling. You have got to use 1000 amp wire and a 1000 amp breaker and that breaker will be Ground Fault Protected.

If you have a question relating to fuse or breaker size, you can reference 240.6(A)

Side note read 240.9 thermal devices. Do you see where it says shall be permitted to be used for protecting motor branch circuit conductors. You will need to know this for your motor calculations.


Index: Taps, Overcurrent protection, 240.21

This section is known as the tap rules.

Highlight: except

Index: Locations. Overcurrent Devices

"Locations" in the index, is a little jewel, just going there now I found a couple of relevant articles I had not thought of recently. This should be explored and committed to memory.

Okay back to Tap Rules. For an expert breakdown of tap rules Click Here on this link and read Mike Holt's explanation.

For testing purposes. Just find the length i.e.10 ft., 25 ft. and look for the word for word answer. Read the question a few times so you will not make any easy mistakes.

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Jim Smith

 Grounding and Bonding


Index: Grounding conductors, Earth as, 250.4(A)

This is not going to be an exam question but it is relevant because when you read section 250.4(A) and the informational note you will realize that grounding conductors have absolutely nothing to do with your installed electrical system.

Read 250.4(A)

Highlight: Limit the voltage imposed by lighting, line surges, or unintentional contact with higher voltage lines and will stabilize the voltage to earth during normal operation.

In short grounding conductors are for lighting strikes and these grounding electrode conductors need to be run as short and straight as possible.

Index: Bonding.

Bonding of electrical equipment shall establish an effective ground-fault current path capable of carrying the maximum fault current likely to be imposed on it section 250.4 (A) and (B). This is so the breaker will trip. The size of the bonding conductors will be from table 250.66

When you look at Bonding in the index you will see the focus is on specific articles in the code book like Aircraft Hangers. If you get a question on bonding, see if a keyword or location is also used. This should lead you in the right direction. 

Exercise: Go to each article or section mentioned in the bonding index and read the article. Seriously each one of these sections is a potential answer.

Highlight: Intersystem bonding in the Bonding index, Definitions 100-I,

Read: section 250.94

This section tells us how we shall provide a bonding point so the cable, telephone, and network guys can attach to it. The intersystem bonding terminal is usually right under the meter connected to the #6 grounding electrode conductor.

Index: Jumpers, Bonding, Piping systems

Read section 250.104

First thing that you will notice about this section is it includes structural metal as well. These bonding jumpers are sized from Table 250.66. Which means they will not be required to be larger than 3/0.

You will notice when you index grounding and bonding that there is almost no mention of articles 250.1 through 250.52.

You will notice on your exam there is no mention either. Your exam does have the following.

·       Grounding electrodes. Ground rods, pipes

·       Grounding electrode conductors. 

·       Equipment grounding conductor sizes

Index: Electrodes, Grounding, Made

Read Grounding and Bonding from section 250.50 to section 250.66. This is where the some of the exam questions are derived from. The majority of exam questions come from Tables 250.66, 250.102(C)(1), and 250.122.

Example question:

What size supply side bonding jumper shall be required for parallel 500 Kcmil conductors?

What is the minimum ft in length a Rod or Pipe Electrode shall be?

What is the minimum distance between two rod type electrodes?

Index: Grounding Electrode Conductors, connection to electrodes, 250 III

Highlight: (just the distances if you prefer).

·       Electrodes permitted

·       Water pipe,10 ft.

·       Concrete encased, 20’

·       Ground ring, 20’

·       Rod and pipe, 8 ft., ¾’’

·       Supplemental electrode, 25 ohms or less, 6 ft. apart

·       Protection Against Physical Damage

·       Continuous

I want you to look at the exceptions (A), (B), and (C) in article 250.66 and Highlight: the different gauges of bare copper that each electrode has for it.

Here is the deal if Table 250.66 requires you to have a 3/0 grounding electrode conductor you are not going to land it on the ground rod. You properly install it on the water pipe ground (within 5 feet of it coming out of the ground) or structural steel.

You are looking for a word for word match with the Table heading the actual tables all kind of look the same. So don’t get in a hurry here.

·       Table 250.66 is the table you will use for the ground wire connected to the structural steel or water pipe. The largest conductor required for 250.66 is 3/0. Be looking for the conductor size.

·       Table 250.102 is the table you will use for any Bonding question with the words grounded, main, system or supply-side. The largest required conductor for Table 250.102(C)(1) is not less than 12 ½ percent of the largest ungrounded supply conductor.

·       Table 250.122 is the table you will the use for the equipment grounding conductor or, the green wire that is in the conduit from the Panel to the equipment fastened in place. Check for the breaker size.

Grounding and Bonding is a big article with lots of potential questions but I have found that most of the NEC test questions are about sizing and using the proper table, or grounding and bonding in specific locations found in the index. 

Before we get started with Chapter 3.

I want to make sure everyone is using the Header of the book (upper corner numbers and words) to find:

·        Keywords in the index

·        Key article numbers in the main body

This will help focus and speed.

How's it going. Good I hope. If you have any questions email me at

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Chapter 3

300 Prepare for Glory

Wiring Methods and Raceways

Here we go. Wiring Methods questions are a little tricky. Depending on the electrical exam you are taking you may or may not have these questions.

Residential Wireman will definitely have these questions.

·       Protection against physical damage

·       notches in wood

·       underground requirements

·       Length of free conductors

Masters, Journeyman and Contractors will have questions like.

·       Raceways exposed to different temperatures

·       Locations

·       Securing and supporting

·       Required boxes and conduit bodies

All will have:

·       Spacing for conductor support

·       Minimum cover requirements

In any case, you shall study everything because it quick and easy.

Index: Protection

Take a minute to read all the items under protection.

Go to Conductors 300.4 this is where we will find some answers.

Highlight: 1 1/4 inch, 1/16 in, 

This is the section about running conductors through bored holes in wood at least 1 ¼ inch from the edge or notching the wood and covering with a nail plate at least 1/16 inch thick.

Index: Underground Wiring

Notice all the possible specific locations and then go to 300.5. All questions will be on Table 300.5. Take some time to study this table. The exam question will give you a scenario and you will have to answer how many inches of cover you will need.

Example question. What is the minimum depth required for 3 phase, 480 volt direct burial wire under an airport runway?

NOTE: Over 1000 volts is table 300.50

Read 300.5(B)

Highlight the part that says the interior of raceways or conduit installed underground is considered a wet location.

Index: Wet Location, Mounting of equipment 300.6(D)

They will give you a location like a car wash and ask you how far from the wall you must stand of your electrical installation.

Highlight :1/4-in

Index: Raceway, Exposed to different temperatures or Expansion Joints, 300.7(A)

When you have some conduit or nipple entering or leaving a building with the outside atmosphere on one side and the climate controlled atmosphere on the inside, right at the point where they meet will condensate during the outside temperature swings. We need to install some duct seal to fill that space and keep the temperature differences separate.

Highlight: filled with an approved material

Section 300.14 is impossible to find during the exam just know it. At least 6'' of free conductor coming out of the raceway into the box. If the box is set back in a wall and you can't get at it, you must have at least 3'' of conductor coming out past the wall.

Index: Raceways, Supporting, conductor’s vertical, 300.19

Highlight: Table, 300.19(A)

Index: conductors, Bending radius

Highlight:8 times, 12 times

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Conductors for General Wiring


Index: Conductors, General wiring

There is a lot of general knowledge here but not many exam questions. Let me explain. 13 pages of article 310 and I have 3 items highlight for you. None of them are direct questions from the test. They are all Adjustment factors.

Please go to article 310 and read section 310.15


310.15(B)(3)(a) More than 3 current carrying conductors.

310.15(B)(4)(d) Not more than 20 current carrying conductors

Know these tables

·        Table 310.15(B)(2)(a)

·        Table 310.15(B)(3)(c)

·        Table 310.15(B)(16)

Take a look at the Table 310.15(B)(16) at the top where it says based on ambient temperature of 86°F. Now look at Table 310.15(B)(2)(a) it also says based on ambient temperature 86°F. This goes for Table 310.15(B)(18) and 310.15(B)(2)(b).

If you get a question that requires you to adjust for ambient temperature most likely you will use Table 310.15(B)(16) and Table 310.15(B)(2)(a). To use the table, you will need the calculated, minimum ampacity needed from the question and the correct column from Table 310.15(B)(16) either 60°C or 75°C. You find the correction factor from Table 310.15(B)(2)(a) by using the temperature range on the right and the correct column. This is a percentage.

Well there is two ways to determine the correct gauge wire.

You multiply the ampacities from the table by the correction factor until you get something close and over the ampacity needed.

Or you can divide the calculated ampacity from the exam question, by the correction factor, to get the minimum ampacity allowed for the temperature, then find the gauge conductor from the table 310.15(B)(16) that will work.

Example: You calculated the conductor feeding a 5 HP, 208 volt, 3-phase motor to be 21 amps. Using the 60°C column from Table 310.15(B)(16) you find you can use #10 gauge wire to feed the motor because it will handle up to 30 amps. Great but the exam question states the motor is operated at an ambient temperature of 117°F. So go to Table 310.15(B)(2)(a) and look at the degrees F on the right hand side. Find 117°F and move over to the 60°C column, your correction factor is .58. You take your 30 amp #10 conductor and multiply it by a correction factor of .58 to see if it will still work for 21 amps. .58 x 30 =17.4 Amps. So #10 gauge will not work. The #10 wire is only good for 17.4 amps at this temperature. You have calculated that you need 21 amps. What do we do? Move on to the next higher gauge wire and solve for the correction factor. #8 AWG is good for 40 amps, multiply that by .58. .58 x 40 = 23.2 or 23 amps. Bingo we can use #8.

With that said what happens if we divide the calculated amperage by the correction factor. 21 amps / .58 = 36.2 amps. You can now find the correct gauge wire from the 60°C column of Table 310.15(B)(16). Still #8 AWG.

If you have temperature and conductor fill correction factors use them both.

Use of Table 310.15(B)(16)

·       under 100 amp use 60°C column

·       over 100 amps use 75°C column

Or use the column stated in the exam question.

If you have any questions or need clarification email me at

It won't hurt you if you take the time to read all the table descriptions in this section. If you see any questions on these tables, I would be happy to hear from you.

Table 310.104(A) is nice for insulation characteristics and applications. Maybe one question here. Trade names.

Index: Conductor, Applications

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Boxes all different styles of boxes, round, 4” square, single gang, 2 gang, octagon, big square boxes 24” x 24”, 4-foot-long narrow boxes, troughs they all have a limited amount of conductors you can jam into them. Section 314 shows you how to calculate the number of conductors.

Index: Boxes, Conductors, number in box

Read section 314.16

Highlight: Volume and fill

This sums it all up for you and your exam questions. You can’t have a volume of wires, clamps, supports and devices greater than your box fill calculated from 314.16(A).

Index: Boxes, Fill calculations

You are going to have multiple questions about boxes The most common question you will have is box fill. Let’s go to section 314.16(B) and read carefully all the sections of box fill Calculations.

Highlight: Double volume allowance for each yoke or strap based on the largest conductor. 314.16(B)(4)

What is a yoke? What is a strap? What is an internal clamp?

I'm glad you asked. These are all things that add to your box fill calculations.


You can't really tell but the yoke or strap is holding this device together. They are the same thing. The metal part of a device with the ears.

Each item in 314.16(B) explains each piece of the fill calculation.

You must take some time and read carefully how many volume allowances are required for each item going into the box.

·       Add the Volume allowances

·       Start with the conductors in table 314.16(B) #18 AWG - #6 AWG

·       One allowance for the grounds (largest conductor)

·       Any clamps or devices specified in the question

·       Find from Table 314.16 the appropriate box style from exam question

·       Minimum volume (inches cubed) of a box that is Greater then your answer

Minimum meaning before you added an extension ring or 2 and a domed cover because you jammed it full.

Index: Boxes again

I want you to look for conductors entering boxes. This section 314.17 is also in conductors.

Index: Conductors and look for boxes. You see 314.17?

The point is that articles that lead to your answer can be found in multiple locations in the index.

Highlight: 1/4''. Find 1/4'' in this article 314.17

Here is another article that is impossible to find during your test.

Flush with combustiblesBoxes concealed behind work such as wood paneling. 

Index: Boxes

Look for concealed work. Go to article 314.20

Highlight: Flush with combustibles

What is the maximum luminary weight that can be supported from a ceiling outlet box?

Don't get caught trying to find this answer in the Luminary section. You could index lighting outlets to get there (round about).

Index: Boxes

Find wall or ceiling. Go to 314.27 Outlet boxes (A) 

Highlight: 50 lbs.

I hope we all realize that if you put an outlet box in the ceiling for a luminary it shall be rated to support 50 lbs.

Index: Pull boxes.

Find 4 AWG and larger conductors. Go to section 314.28

The question here is what is the minimum size pull box you can use with x number of conduits entering the pull box. 

Straight Pulls

·       8 times the largest conduit

·       length of the box

Angle Pulls

·       6 times the largest conduit

·       plus, the sum of the conduits in the same row

·       use the largest row

·       distance between the sides of the box

You have to determine the largest row on the box separately.


Getting questions on cable, different types of cable AC, MC, NMB whatever is always nice. It’s like taking a break. You know where they are in the index, the question is always specific to what cable they are looking for and the articles are short and sweet.

Index: Cables

Now none of the articles reference numbers are actually here for specific cables but it tells where each of them Shall be found in the index. For example, look for tray cable (TC) just look for the letters TC. It probably did not take you that long to find out that TC cable is found under Power and Control tray cable in the index.

Index: AC

Index: Armored Cable

Which of the subsections of Armored Cable would you find this answer? Can you use Armored Cable in a damp location?

You are correct! Uses not permitted.

Please turn to section 320.12 and find the uses not permitted for Armored Cable.

You will find that all cable articles have these 2 sections Uses Permitted and Uses Not Permitted.

Note: Everyone should read MC and NMB articles thoroughly just as a minimum. 


Conduit and other Raceways

Conduit and other raceways is the same thing. Very specific questions about different conduit materials like Rigid, IMC, or PVC. All of these easily found in the index.

Index: Conduits

You will see a list of all the different conduits and where to find them in the index. 

Index: Intermediate Metal Conduit

As you can see the article and section number to find out everything you would ever want to know about IMC is listed here in the index under Intermediate metal conduit.


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Chapter 4

400 Motorhead

Index: Flexible cords

Now index: Cords, Flexible

Note: I call it like I see it and you will have to as well if the keyword in the question is flexible cord then go for it but be mentally prepared to adjust quickly.

Now that we are at chords, flexible let find all the references to article 400. Do you see insulation Table? Let’s go to it at 400.4

Table 400.4

What you need to know here is the USE and the TYPE but you can read all the trade names as well. I am sure you will see some you recognize like refrigerator cord, dryer cord, SO cord.

What type of cord can I use for my two-fer if I need a Hard Usage cord? 




C. SPT-3



A two-fer by the way is a one in two out cord used on stage.


Index: Cords, flexible

Here again we have uses not permitted. Turn to section 400.8

Highlight: dropped ceilings.

Index: Tables. Look for flexible cords and fixture wire.

This might save you some time in the long run.


When installing switches in a single family dwelling. The switch handle shall not be over ___ft____in above the floor at its highest position.

What keyword do you think should we index?

If you guessed switch we are on the right track.

Let’s index switch and find the Accessibility and Grouping section.

Right there in 404.8(A) Highlight: 6 ft 7 in

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Okay let’s see what we get here.

I have a couple articles to highlight here but I think when you Index: Receptacles you will find that most of the references are not for Article 406. I will do some foreshadowing for you here. Here are some definite exam questions from the Receptacles index.

1.    Anesthetizing Locations

2.    Electrical vehicle charging locations

3.    Electrified truck parking spaces

4.    health care facilities

5.    mobile homes

6.    Patient bed locations

7.    recreational vehicle

8.    show windows

9.    swimming pools

10. Replacements

Start with replacements and will get to the others in their respective article.

Section 406.4(D)(2) Non-grounding receptacles

Highlight: No equipment ground and GFCI protected.

Index: Receptacles

Look for Weather resistant. Let's go to section 406.9(A) Damp Locations.

Highlight: Covered


This is a big Article and the proper amount of time should be taken to read carefully. In my experience most of the exam questions focus on locations.

Let’s index: Luminaries

It is much easier to see the exam question by looking at the index then reading the article.

I expect that you are reading the entire article sections mentioned here.

1.    Bath tubs, near 410.10(D) Highlight: 3 ft and 8 ft

2.    Clothes closets 410.16 Highlight: (C) location

3.    Supports 410-IV Highlight: 6 lbs. and screw shell of a lampholder.

4.    Grounding 410-V Highlight: GFCI protected (exception)

5.    Raceways 410.64 Highlight: end to end

6.    Wiring 410.117 Highlight: Tap Conductors and notice the distances.

These are hard questions to answer during the exam so I'm going to tell you a story so maybe we can all remember without having to find out exactly the article and section to find the word for word answer.

Have you ever been taking a shower somewhere and swear that you can change the light bulb in the vanity and still be in the tub. Yeah, you might get electrocuted doing that so let’s keep those luminaries at 3' horizontal and 8' vertical. So you get out of the bath room and walk over to the closet. You open the closet and some sheets and blankets on the top shelf are discolored from heat because of how close the lamp is to them. A single open bulb might be a fire hazard so keep our closed luminaries at least a foot away from any point of storage.

So we wander into the reception area of the motel and there hanging from the ceiling is a 4' wide antler chandelier being supported by the little screws holding the canopy. Don't stand under it.

The game room though is okay because it has fluorescent lights wired end to end and you know these luminaries are rated to be raceways but you will just have to hope that the wall sconce is GFCI protected because you can see the equipment grounding conductor hanging out of the bottom.

Okay now back to the index.

Index: Poles, Supporting luminaries

and go to 410.30(B) Exception No. 1

Highlight: 8'

410.30(B) Exception No. 2

Highlight: 20' hinged base.


Index: Cords, Flexible

The section we are trying to get to is Appliances, Flexible cords article 422 section 422.16.

You can see in the index under cords it just says flexible. You will probably have to just keep your place in the index and flip back and forth. Actually you have to do this a lot. If the index gives you a list of article sections, you will need to quickly determine which of these sections are relevant.

If the question is: What is the maximum length for a kitchen waste disposer flexible cord? I would start by indexing Appliances then go to flexible cords then go to each section listed.

Best case scenario.

Let's exerciser this now by doing that exact thing. Quickly

·        Index appliance

·        go to chords flexible

·        keep your place in the index with one hand while you find article 400 (you see it's not exactly what you are looking for).

·        next go to article 422.43 you see this is for heaters and bounce

·        go to article 422.16. Now you see that you are in the right area and scrolling down you can locate the number you are looking for because it is one of the answers on your testing screen 36"

Highlight: Waste Disposers, Dishwasher, Trash Compactor also you can highlight the lengths if you want. 

Index: Fountains

Notice. Electric drinking fountains.

Go to section 422.52 and Highlight: GFCI

This is interesting because this section is not in Appliances, electric or drinking it's in Fountains

Fixed Electric Space Heating


The Branch circuits for fixed electric space heating shall be rated 15,20,25,30 amps.

Non-dwelling units can have fixed space heating up 50 amps.

Fixed electric space heating is considered a continuous load. When calculating the branch circuit for fixed electric space heating you will use 125% of the current rating for the heater.

Let's go to the index for fixed electric space heating. 

You will see a ton of sections here and they are all in article 424. Just take some time to read them all I don't know exactly what question you will get. If you are up north, you will surely get one or two. You should have the skills to dig them from this index though.

Highlight:  30 amps, duct heaters, clearance of wiring above heated ceilings.

Fixed outdoor Electric Deicing and Snow Melting Equipment

Attention: Florida you will not have any of these questions.

The key element to snow melting is that it must be GFCI protected but that GFCI must be rated for equipment. If any of you have ever been popped for this by your local authority having jurisdiction you know the difference.

The GFCI for equipment is 20 mA trip rated and opens all ungrounded conductors.

Index: Fixed outdoor electric deicing, Ground Fault Circuit Interrupters

This is interesting because you can find it 2 different places in the same index. This happens sometimes and you’re in such a rush to find the answer you just go with the first one and it leads you right back the article you were just in!

Go to Ground Fault Circuit Interrupters, 210.8(A)(3) Ex. it leads your right back to 426.28 but if you look at the index again under Protection you'll see it has both sections.

Highlight: Equipment

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Everybody misses motor questions and I don't care if you install motors all day long. I’ll tell you why.

Unless you are the one designing the system everything you need is either delivered or is already there or marked on a set of plans like.

1'' Conduit run with 3 - #6 THHN from service panel PP2 to the multiple motor disconnect out of that run 3/4'' EMT with 4- #10 to the frequency drive (motor controller) from freak drive to the motor with 3/4'' flex with 4 - #10 THHN.

You know what I mean? You did not have to sit down and figure out all the different little things that go into:

1.    Motor

2.    Motor Feeder, motor circuit conductor

3.    Motor Overload Protection

4.    Motor Branch-circuit and Short-circuit Protection

5.    Motor Feeder short-circuit and ground fault protection

6.    Motor control circuits

7.    Motor Controller

8.    Motor Disconnecting Means

The motor section is going to be a little different because what we are studying is not necessarily an answer to the Exam question but a valuable piece of the calculation.

Let's begin by following along with the study guide and reading some sections of Article 430

430.2 Definitions

What is a motor controller?

A motor must have a controller. A switch or device that is used to start or stop a motor is a motor controller.

Figure 430.1

Here we see a figure of the entire motor electrical system.

This figure comes in very handy when you’re trying to figure out exactly what the exam question is asking. You can use the picture to find the part in the system you are working on then above the pictures it tells you the section number. 

Take a couple of minutes, or hours, and go to each page or group of pages represented in the upper half of figure 430.1 part by part.

Part I - Part XIV

Highlight: Tables, Tables 430.247 through 430.251(B) Part XIV


·        Your conductor sizes shall be from Table 310.15(B)(16)

430.6(A)(1) This is huge!

·        Values given in Table 430.247, Table 430.248, Table 430.249, or Table 430.250.

·        Shall be used to determine:

·        Ampacity of conductors (Part II)

·        Ratings of switches (Part IX)

·        Branch short-circuit Ground fault protection (Part IV)

·        INSTEAD of the actual current marked on the Motor nameplate.

You can highlight this whole section 430.6(A)(1)!

So many guys miss motor questions because they don't look at the Tables.

You can't find the correct conductor, switch, or Branch short-circuit Ground fault protection size (meaning gauge of the feeder conductors, amperage of the switches, or the breaker in the panel) unless the you find the motor first, in Table 430.247, Table 430.248, Table 430.249, or Table 430.250.

430.6(A)(2) Nameplate Values

So then what is the nameplate current rating used for? I'm glad you asked.

Separate motor overload protection

What is separate motor overload protection and thermal protection? Part III Please look at Figure 430.1 and notice the locations of part III. Now look above and find pages 430.31 through 430.44.

We will discuss more about overload protection in section 430.31 but for now let's just say that motor controllers sometimes have things called heaters that protect the motor and conductors or it could be a fused disconnect with overload rated fuses.

430.7 Markings on Motors

430.7(A) is the required segments on the motor Name Plate



What does locked rotor mean?


Locked Rotor from Jim Smith on Vimeo

If you can't watch the video because your listening to the audio version of the study guide a locked rotor means a rotor which is not moving. If the power is applied to the stator and the rotor is not moving the rotating magnetic field of the stator will be inducing the maximum inrush current onto the rotor.  

The in rush current will stay hi until the rotor starts spinning.

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Single Motor Conductors

430 II. Motor Circuit Conductors

Please refer to figure 430.1 and notice on the drawing where Part II is used.

Motor feeder, Motor circuit conductor, secondary conductors, secondary resistors.

430.22 Single Motor

Your exam is going to have motor questions. The question is going to be about feeding a single motor or it is going to be about feeding multiple motors.

If the question is about conductors feeding a single motor,

remember, we shall determine ampacities for conductors using tables 430.247 - 430.248

then it will be 125% of the amperage from the Tables.

A different way to say it is multiply whatever the amperage you get from Table 430.247, Table 430.248, Table 430.249, or Table 430.250 by 1.25

That's it 75% of your questions are going to be. What is the size feeder conductor will you need to supply a single 5 HP, AC, 3 phase motor at 208 volts?

Just go to Table 430.250 AC 3-phase motors, look up 5 HP, 208 volt find the amperage 16.7 amps

Multiply 16.7 by 1.25 = 20.875 amps

go to Table 310.15(B)(16) using the 60° column (less than 100 amps) and see you will need to feed the motor with # 10 AWG wire.

Easy right. Well honestly you will be lucky if you get a question this easy. Nevertheless, if you do, this is how you do it.

Index: Motors, conductors, single motor

Note all the references to 430.22 and absorb the different types of motors here.

Now let’s go back to 430.22 and look at some different types of single motors.

·        Direct-current

·        Multispeed

·        Wye-start delta-run

·        Short- time duty

·        Intermittent duty

·        Periodic duty

·        Varying speed duty

Note for the last 4 motors. Your electrical exam question will either be on a continuous duty motor or it will be on a Duty- cycle motor.


Don't forget what section we are in here guys. We are in conductors and this table says Duty cycle motors are allowed to derate their nameplate current to find the conductor size.

Say you have a 15 minute rated, intermittent duty, motor with a nameplate current of 17.5 amps. What is the minimum gauge wire allowed? Find intermittent duty in the table do you see the time? and do you see 85% good.

17.5 Amps x .85 = 14.85 Amps round up to 15 Amps

Table 310.15(B)(16) 60° column your answer 14 AWG

Ok let's Highlight some things here. Find all the sections with 125% and highlight125 %

If you get lost this is you go to number, you are never just going to read the nameplate and size the CONDUCTOR for it. It will more than likely be multiplying the amperage from the tables by 1.25

430.22(E) highlight: Conductors, not less than the percentage.

If you haven't yet gone back and read 430.6(A)(1) this just says use the Table 430.247, Table 430.248, Table 430.249, or Table 430.250.

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Multiple Motors Conductors

430.24 Several Motors or Motor(s) and other Loads

Example question: An office building mechanical room has 2- 5 HP, AC, 208 volt, 3- phase motors, 3- 1 1/2 HP, DC, 120 volt, motors, 3- 12.5 amp non-continuous non-motor loads and 21.6 amp heater. 


·        125% of the largest motor load

·        sum of the amperages from Table 430.247, Table 430.248, Table 430.249, or Table 430.250. for all other motors in the group

·        100 % of all non-continuous non-motor loads

·        125% of the continuous non-motor loads

First to find the largest motor load (from the tables) and multiply by 125%

1.    5 HP, AC, 208 volt, 3 phase = 16.7 Amps This is our largest motor load. 16.7 Amps x 1.25 =20.875 Amps

2.    1 1/2 HP, DC, 120 volt = 13.2 Amps x 3

3.    12.5 amp x 3 = 37.5

4.    21.6 Amps x 1.25 = 27

5.    Total Amps 127 amps. (rounded up per Section 220.5(B))

6.    Go to table 310.15(B)(16) to the 75° column (over 100 amps) and find the conductor rated for more than 127 Amps

Sample of what your scratch paper would look like. The testing facility will provide scratch paper for you.


III Motor and Branch circuit overload protection

First thing you need to understand about overload protection is located in 430.32(C).

Highlight: overload device shall have sufficient delay to permit the motor to start and accelerate its load.

Now that this is said, let’s talk about it.

What we are going to need is a device that will allow for the maximum ampacity of inrush current for a certain amount of time.

This will allow the motor time to get going and the current to comeback down to running current.

The devices we use are called: Thermal overload heaters, Thermal protection, Overload relays, Electronic motor protection relays, Time delay fuses, Heating elements for motor starters.

I think you get the point that the conductor is going to be sized for the full load current (running current) not the inrush current.

So if the motor starts to fail and is drawing more current than it’s running current for a certain length of time the thermal protection will be the device that protects the motor and the conductors.

Index: Motors, Continuous Duty



·        Motors marked with a service factor of 1.15 or greater

·        Motors marked with a temp rise of 40° C

·        All other motors

Note that most motors you will encounter will be rated with a service factor of 1.15 also note that these are motors rated more than 1 horse power. Not your garbage disposal.

IV Motor Branch circuits and Ground Fault Protection

This is where things get interesting. You know that we have the motor and conductors protected already by the thermal protection so what size breaker are we going to feed the motor controller.

If we feed the motor controller with a 20 amp instantaneous breaker because the motors full load current is 16 amps and 16 x 1.25 20 amps so that is what our conductors are rated for what happens when the motor inrush current is 32 amps?

What happens is the breaker trips.

That is called nuisance tripping.

So what do we do?

Since we have the motor and conductors protected from overcurrent (within a certain length of time) by the heaters we can up the size of the breaker in the panel as long as it trips on ground faults and shorts.

For an instantaneous trip breaker feeding a Squirrel Cage motor we can go as much as 800 % (MAX) of full load current.

Let’s see that is 16 x 8 =128 Amps

So let’s put that 16 amp motor on a 100 amp breaker and feed it with #12 AWG conductors. This would be an extreme case and I don’t know if the electrical inspector would like it. Though it would be totally legal.

Highlight: Table 430.52

What this table is showing us is all the different breakers and fuses for certain types motors that can be used to prevent nuisance tripping.

VII Motor Controllers


·       430.81 (A) 1/8th HP,

·       430.81(B) 1/3 HP,

·       430.83(A)(3)(C) general use snap switch -80%


Things to remember

1.     The figure 430.1

2.    430.6 Ampacity of conductors comes from the Tables XIV

3.    Overload Protection comes from the Nameplate Values

4.    Why locked rotor is important

5.    125%

6.    430.24 Several motors or a motor(s) and other loads

7.    Overload device shall have sufficient time delay to permit the motor to start and accelerate

8.    Table 430.52 Branch short circuit and ground fault protective devices

9.    Tables XIV


Air conditioning and refrigerating equipment

Highlight: section 440.22 Increased but shall not exceed 225%

Highlight: section 440.32 Single Motor Compressor 125%, 72%

Highlight: Section 440.52(3) Fuse or inverse time circuit breaker 125%

Highlight: Section 440.62 80% and 50%


If you read the respective article I think you’ll get the point. I haven’t heard any guys telling me they got stumped by the air conditioner question so I’m guessing you won’t either. If you do call me at 970-531-1973 and let me know.


Generators Article 445




Transformers can go either way sometimes your exam will only have one then I talk to guys that had 5 transformer questions are their electrical exam.

So be prepared two answer all different types of transformer questions. Most of them will be on the Table below 1000 volts.

So let us start with the Tables 450.3(A) and 450.3(B)

1.     450.3(A) is over 1000 volts

2.    450.3(B) is under 1000 volts

3.    Both tables have extensive notes underneath that need to be read.

Index: Transformers, Dry type

 450.21 Dry type Transformers

Highlight (A) not over 112 ½ KVA and 12’’ from combustibles

450.22 Dry-Type Transformers installed outdoors 12’’ from combustibles


Capacitors article 460

460.2 Enclosing and guarding

Highlight 3 gallons


460.6(A) Time of discharge

Highlight: 50 volts

Storage Batteries Article 480

You can say there has been some changes in the battery world in the last 3 years.

This exam question is in the definition which is always in the .2. I think we discussed that earlier though.

Read 480.2 Please

Highlight:  in the informational note

·       2-volts per cell (lead acid)

·       1.2-volts per cell for alkali

·       3.6-3.8 volts per cell (Li-ion)

That is all I have for you but I get the feeling more and more battery questions will be coming so at least read the entire article.

Is it me or was Chapter 4 GOLD! MOTORHEAD

You know the NEC and this study guide have 9 chapters. Questions or comments

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Chapter 5

The 500's

Article 500 Hazardous (classified) Locations, Classes I, II, and III, Division 1 and 2


Article 500 Hazardous (classified) Locations, Classes I, II, and III, Division 1 and 2

Electrical exam questions about hazardous locations will typically give you a scenario where you will have to choose the correct class I, II, or III and Division 1 or 2.

Start off by reading the definitions in section 500.2 so you can get the feel for what we are about to get into.

I’m getting the feeling they don’t want any sparks. Sorry I mean incendiary components.

We will need to get familiar with the way hazardous locations is laid out in the index.

Index Hazardous atmospheres

The meat of section 500 starts with 500.5 which you can see here Hazardous atmospheres

·       Class I locations

·       Class II location

·       Class III location

To exam takers this is everything.

500.5 (B) Class I, Division 1. Where combustible vapors are present.

Highlight: Flammable, gases or vapors, present

(Less is more, with your highlighter here)

Read the informational notes

500.5(2) Class I, Division 2 Where the combustible vapors pass through but are not stored or are worked with but in closed containers

Highlight: Adjacent to class I, Division 1

500.5(C) Class II, Division 1. Where combustible dust is present. I always think of like a silo full of grain but you can choose your own dusty place.

Highlight: combustible dust

500.5(2) Class II Division 2 A place where it’s possible an accident could produce combustible dust.

Highlight: Combustible, Dust, could, become suspended in air

500.5(D) Class III, Division 1 we got some fibers flying around in concentrations that are combustible.

Read the informational notes

Highlight: Ignitable fibers

500.5(2) Class III, Division 2this is where the fibers are stored but not manufactured.

Highlight: fibers, stored


Don’t rely on your memory HERE

Use the book. As a matter of fact

Highlight: 500.5 Classification of locations

Make sure you know exactly which location (Class and division) the question is asking.

There is no reason to miss an easy question to gain a little time. I can’t tell you, how guys kick themselves for missing easy questions. Especially when they fail by only one or two questions.

Find protection techniques in the index under hazardous locations.

When you have explosive atmosphere you need to do your work in a manner that is proven to be safe for the area. The reason they wrote this code and the reason it looks like lawyers wrote it is because each time an electrical installation did not work somebody blew themselves up.

Needless to say a lot of trial and error went into these techniques so we the electricians can learn from the guys before us.

Any way if you are looking at the index it pretty much follows the articles in the main section. So if you want to find something in the beginning of Article 500 Hazardous (classified) Locations it will be in the beginning of the index.

So let’s look in the index at protection techniques. The one toward the beginning of Hazardous Locations.

500.7: Protection techniques

Notice that each one of these techniques is for a different location. With some backward redundancy. Meaning you can use a stronger protection for a division 2 location but you can’t use a weaker protection in a division 1 location.

Example question: A chemical plant that makes volatile flammable liquids has an area where they are pouring into open barrels. You must install an outlet for a piece of equipment 18 ‘’ off the floor. What type of protection technique will you utilize?

A.   Explosion proof

B.   Dusttight

C.   Dust ignitionproof

Index: Hazardous (classified) Locations, Classes I,

Read every sub section of the index from Bonding to Zone equipment.

Index: Hazardous (classified) Locations, Classes II

Read every sub section of the index from Bonding to Zone equipment

Index: Hazardous (classified) Locations, Classes III

Read every sub section of the index from Bonding to Zone equipment

I’m Starting to see a pattern here.

If you get in a hurry and you are looking for bonding in a hazardous location, you are going to find it but you can also find it 5 other places in the index. So make sure first you know your location.

Commercial Garages


Start with the definitions .2

511.2 Read the differences between major repair and minor repair.

Index Garage

The main thing we are concerned with is area classification. In places where there is going to be hazardous locations the test is going to be on, in and around wiring in those areas.

I don’t see exactly what I’m looking for in the index so we are going to have to replace area classification with ventilation.

511.3(C) through (E)


Major Repair

·       Ventilation provide 12’’

·       Ventilation not provide 18’’

·       Ventilation ceiling unclassified

·       Pits 6 changes per hour


Minor repair

511.7 The test loves areas above hazardous locations so when you see these articles pay attention.

Aircraft Hangers


Notice the locations like Stanchions and docks 513.7 (E) and painting hangers.

The questions will most likely be on the fringe areas and the floor areas. Because of accidental spells of fuels anything from the floor up to 18’’ is considered a class 1 location

The distances in the painting hanger is a good one as well (class I division 1 or 2). Try to imagine the plane in a box the box is 10’ from any surface of the plane this is Class 1 Division 1. Now put that box into another bigger box that is 30’ from any surface of the plane that’s the Class 1 division 2 area.

Bulk Storage plants


Not much to say here

Index bulk storage plant, class 1 location take a look at the table.

515.7 wiring and equipment above a class 1 location


Spray, Dipping and Coating


Just make sure you can find it in your index and make sure you understand what all the figures Area Classifications mean.

Figure 516.3(D)(6)(a) 

Health Care Facilities


517.1 through 517.35 is our focus and where 90% of exams have questions so let’s break it down a little.

Start with the definitions in 517.2

Read and highlight the following

·       Critical Branch

·       Essential Electrical System

·       Life Safety Branch

·       Patient Car Vicinity, 6’ and 7’6’’

Next Highlight

517.7 Ground-Fault Protection, 100% selectivity


General care areas


eight receptacles

Pediatric, tamper-resistant


Critical care areas


14 receptacles

36 receptacles

Read 517.21


·       shall not be required


Essential Electrical System required for hospitals

Look at informational note Figure 517.30 No.1 and No.2

Essential electrical systems shall be comprised of three separate branches


·       Life safety Branch

·       Critical Branch

·       Equipment branch

Of course you have your Nonessential branch supplied by the normal source as well.


517.32 Life safety Branch

supplies the power of the generator to illumination of the means of egress like stairs, exit doors and corridors. As well as exit signs, fire alarms and elevators.

517.33 Critical Branch

supplies the power of the generator to task illumination and selected receptacles for critical care areas, patient care areas, nurse call, emergency room treatment areas, Intensive care units this is not everything that is listed but as you can see these areas are where people are getting worked on.

517.34 Equipment Branch

Equipment can be delayed to start. Imagine if every motor in the hospital started at the same time as the other limited lighting and receptacle circuits. You would risk the generator going out on overload.

Equipment branch circuits include suction, sump pumps, compressed air, kitchen hoods, and HVAC

Now let’s highlight something.


Within 10 seconds

This is the maximum time allowed to re-energize critical and life safety circuits.


Articles 518, 520, 522, 525, 530, 540, 545, 547,

These articles are all one hit wonders. I have no doubt by now that you can use the index and your deduction skills to pull a couple of word for word answers from these articles. If you do come across something on your electrical exam you think I’m missing here please please contact me

That being said take the time to at least read the definitions in the .2’s so if you do get a question it’s not a big shock.

I do have a couple of items of interest.


Highlight 100 or more persons and read the article


Familiarize yourself with the definitions, notice as you skim the sections that all the cords are rated for extra hard usage this goes back to Table 400.4.


520.10 portable equipment, barrier

520.69, two-fers

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Mobile Homes


A mobile home is factory wired so there isn’t a lot of questions on the actually wiring but more questions on the hook up and services.

The first section we will cover is 550.10 Power supply.

Highlight: not more than one 50 amp cord or permanently installed feeder.

550.10(A) Ex No 1

Highlight: 40 Amperes

550.10(C) Attachment plug

Highlight: 3-pole 4-wire, grounding type, rated 50 amperes

550 III

Services and feeders

Example question: You have a mobile home park with 32 lots. What is the minimum size conductors used to feed the service?

16000 volt-amperes x 32 lots = 512,000 volt-amperes

32 lots have a demand factor of 24% so multiply 512,000 x .24 = 122,880 volt-amperes

Mobile home lots are single phase 240 volt

Divide 122,880 volt-amperes by 240 volts = 512 Amps

Go to Table 310.15(B)(16) 75° column (over 100 amps)

Answer 900 Kcmil or parallel 300 Kcmil


Recreational Vehicles and Recreational Parks

Definitions 551.2


Means for connecting power supply

Attachments plugs

Highlight 15 amp, 20 amp, 50 amp

551.73 Calculated Load

Example question:

You have a recreational park with 25 sites. Utility is 120/240 volt

10 of the sites are 50 amp

5 sites are of the 20 or 30 amp variety

5 sites are 20 amp only

5 other site are tent sites

What size service conductors would we need to feed this Park?

50 amp sites are calculated at 9600 VA

20 or 30 amp sites at 3600 VA

20 amp sites at 2400 VA

Tent sites 600 VA

That is

10 x 9600 = 96000 VA

5 x 3600 = 18000

5 x 2400 = 12000

5 x 600 = 3000

Answer 129,000 VA

Table 551.73(A) say the demand factor for 25 sites is 42%

So 129,000 VA x .42 = 54180 VA The utility is 240 volts so divide

54180 / 240 volts = 225.75 round up for 226 Amps

Table 310.15(B)(16), 75° column

Answer 4/0 copper

Floating Building and Marinas and Boat Yards

553 and 555

Marinas and boat yards are my favorite sections. I guess it’s because I’ve always wanted to live on a boat. The questions are varied around the country but obviously if you are near the water you may get more questions. Together you should read both articles and get familiar with the service and wiring methods.

555.2 Definitions

Electrical Datum Plane


·       In land areas, 2’, High Tide

·       In land areas, 2’ highest water level

·       Floating piers, 30’’ above water and 12’’ above the dock

·       555.4 1000 volts

555.13 Wiring Methods

Highlight: 555.13(B) wiring over Navigable waters

Also take note that the jacket used for portable power cable is going to be rated for extra-hard usage and resistance to weather extremes, oil, gas, ozone, abrasions, acid and chemicals.

555.19 Receptacles


·       Receptacles shall be listed as Marina power outlets

·       Strain relief

·       Ratings (a) and (b)

Like I mentioned there is a lot of potential questions here whether you get any questions is up to the code makers in your area. 


One more thing find all the sections dealing with GFCI's and trip ratings.

Temp Power


Have you ever installed temp power? Well I’m sure you have read Article 590. What! You haven’t read article 590?

This is probably because you just used some common sense and general knowledge of other articles in the code. Now is the perfect time to read it so let’s start with:

 590 Time Constraints.

Let’s just say I probably still have some temporaries out there. Don’t call the inspector.

If you’re not me though you should only have the temp. service, there for the particular project then pick it up immediately after the job is complete.

Also only 90 days on those temp Holiday lights please.

Highlight: 590.4(H) Protection from damage

590.6 GFCI

Highlight: everywhere it says personnel

Index, Article, Highlight. Index, Article, Highlight. Index, Article, Highlight. Speed, Focus your getting there. Just 3 more chapters.

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Jim Smith

Chapter 6

600 Almost home

The 600’s. We are going to focus on the major sections of 600 like signs, swimming pools, and Solar Photovoltaic. When we pass answers that need to be highlighted we will Index and highlight. I don’t want you to start overloading you with little one hit sections like Office furniture.

Electric Signs and Lighting


I get a lot of people asking me about signs. This is a hot subject so read this Article 600 carefully

Start with the definitions and branch circuits these are the major sources of questions for signs.

Example Question: Can you use a 120 volt sign as a junction box to feed another 120 volt sign?

Index: Signs, Enclosures 600.8

Highlight: permitted as pull or junction boxes.

Look at 600.5(C)(3) Metal or non-metallic poles. It says must be installed in accordance with 410.30(B)

Index: Poles, Supporting luminaries

Highlight: 410.30(B)

600.8 Enclosures

Highlight .020 thick

600.9 Location

Highlight: 14’

You will get a voltage drop question. It will either be for a sign or a motor or both. Here is an example of a sign voltage drop calculation question.

What is the minimum size conductor you can run underground to a single phase 208 volt +/- 3% sign that draws a current of 7.5 amps? The sign is 200 feet from the source.

Signs are considered a continuous load because they operate over 3 hours. Remember that branch circuit conductors supplying continuous loads shall have an allowable ampacity of not less than 125% of the continuous load (210.19(A)(1)(a).

First find the max VD for 208 volts +/-3%. 208 x .03 = 6.24 Volts.

Next find the amperage 7.5 x 1.25 = 9.375 Amps

If you are allowed to use an Ugly’s book on your exam open it now and reference the voltage drop formulas (VD) around page 50.

If you have to memorize this formula, please memorize it now.


2 x 12.9 x 9.375 x 200 / 6.24

2 = single phase

K = 12.9 (this is the resistivity for copper at 75@C and can’t be found in your code book)

9.375 = the current draw of the sign. (Any load that operates over 3 hours is a continuous load and should be rated 125% for conductors.)

L = Length of run.

VD = Calculated voltage drop or just the voltage drop if they give it to you.


CM = 7752

Circular mils from Chapter 9, Table 8, Conductor Properties

Find the Size that is just over your CM.

10 AWG = 10380 Circular mils

More on the Tables when you get to chapter 9

Electrified truck parking

Index: Electrified truck parking space equipment, Wiring systems

Highlight: 626.22(B) mounting height

Electric Welders


·       630.11(B) How to find the conductor ampacity of multiple Arc welders.

·       630.12, 200%

Information Technology Equipment


·       645.5 Supply circuits, data processing, 125%

·       Table 645.5 Cable types permitted under floors


Irrigation Machines

Highlight: 675.11 collector ring 125%

Swimming Pools, Spas, Hot Tubs


Anyone who has ever wired a pool either in-ground or above ground knows you don’t just hook the feeders to the pump and walk away.

You have extensive equipotential bonding, GFCI requirements, required receptacles, and. luminaries both wet and dry niche that need to be addressed. The electrical exam will ask questions about all of these things and more.

You will also have questions about things around the pool such as festoon lighting, and overhead conductor clearance’s.

I. General

II. Permanently Installed Pools

III. Storable pools

IV. Spas and Hot Tubs

V. Fountains

VI. Pools and Tubs for Therapeutic use

We will start at definitions 680.2 with:

·       Maximum water level- The highest level the water can reach before it spills out.

·       Storable swimming pool- Those constructed above ground and can hold water to a max depth of 42’’

Now go to index and look at swimming pools.

Look for overhead conductor clearances and go to 680.8. When you get there look for two Tables concerning conductor and cable clearances most of the questions on the section will test your ability to use these Tables 680.8(A). Read the clearance parameters from the table.

680.10 Underground wiring location

Highlight 5’ horizontally

680.12 Maintenance disconnecting Means

Highlight: readily accessible, 5’ or permanently installed barrier that provides a 5’ reach path or greater.

680.21 Motors

Highlight: 680.21(A)(1) General, not smaller than 12 AWG

Index: Receptacles, Swimming pools

Each section listed here is a potential answer.


·       680.22(A)(1) Required receptacle location, no fewer than one general-purpose receptacle not less than 6’ from and within 20’

·       680.32 GFCI required within 20’ of the inside wall of the hot tub

·       680.34 Receptacle location shall not be located within 6’ of the storable pool or hot tub or spa

·       680.43(A) Required receptacle location, no fewer than one general-purpose receptacle not less than 6’ from and within 10’ from the inside wall of the Hot tub

·       680.62(E) Therapeutic Tubs, Receptacles within 6’ of the tub shall be GFCI protected.

Index: Swimming pools, Pool water heaters

Go to 680.9

Highlight not exceeding 48 amperes.

Index: Luminaries, swimming pools, spas

This is pretty much the same as receptacles (swimming pools) where you can find an answer for each of the sections listed here.


·       680.22(B) Outdoor clearances, within 5’ of the pool, shall be not less than 12’ high.

·       680.23 underwater luminaries, (find) not less than 18 in from the normal water line.

·       680.26(B)(4) Underwater lighting, shall be bonded

·       680.43(B) Elevation, over hot tubs indoors, (a)without GFCI protection 12’, (b)with GFCI protection 7’6’’(c) below 7’6’’


Index swimming pools bonding

Highlight in the swimming pool section

·       680.26 Equipotential Bonding (this is a big section so take some time and look over)

Notice that this is in the 680 part II and the part II means Permanently Installed Pools.

The point being if you just flip to it from the index you don’t know whether you are looking at equipotential bonding for in-ground pools or a hot tub so flip back pages until you find exactly what part you’re looking at.


·       680.26(C) Pool Water, 9in squared

Article 682 Natural and artificially Made bodies of Water

Read article 682 and

Highlight: 682.33 (C) 8 AWG

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Solar Photovoltaic


This is probably the fastest changing article on the electrical exam. As we install solar cells by the thousands we gain more knowledge about the procedures that need to followed to keep everyone safe.

Even though this article is going to have the newest exam questions we will treat it the same way as other articles. We will read the definitions in the .2 and use our index to find the key word from the exam question.

Please find solar photovoltaic in your index.

Look for Maximum Voltage

Go to 690.7


·       Table 690.7(A) DC, shall be used to find the correct voltage rating of cables, disconnects, overcurrent equipment

·       690.7(C) in one and two family dwellings 600 Volts shall be permitted Maximum

Next let’s look at circuit sizing of Solar photovoltaic systems in the index and go to 690.8(1)

Highlight: Maximum current shall be the sum of the parallel module rated shot-circuit currents multiplied by 125 %

Index Solar photovoltaic systems, overcurrent protection

Highlight: Section 690.9 Overcurrent Protection

Index: Solar photovoltaic systems Storage batteries

Highlight: 2 volt-cells

Fire Pumps


Index: fire pumps

Find power sources to electrically driven motors.

The thing about fire pumps that sets them apart is they are allowed to have a separate service and disconnecting means.

Which makes sense because you don’t want the fire department to show up to a burning building, kill the power for their safety, and have the fire pump shut down.

Turn to Section 695.3 and

Highlight: supplied by a separate service

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Chapter 7


In this chapter we take a look at some answers to generator questions in emergency systems, and Stand-by systems, then get into the Low Voltage Sections of the code book including control circuits, fire alarm and optical fiber. You want to be aware of any substitute cables we can use in these sections.

Emergency Systems

Please read the informational note in the definitions 700.2 Emergency systems.

Now please find sources of power under emergency systems in your index.

700 III

700.12(A) Storage Battery, (batteries must maintain total load for a minimum 1 ½ hours, without the voltage applied dropping below 87 ½%)


·       1 ½ Hours

·       87 ½%

Index: Generator, emergency systems


The generator set shall have a time delay feature permitting 15 minutes of run after the power is restored to make sure the normal load is not flickering on and off. The generator is also required to have at least 2 hours of fuel on premise.


·       1 1/2 hours

·       87 ½%

·       15- minutes

·       2 hours

700.12(B)(6) outdoor gen set


Disconnecting means within sight.


Low Voltage


Class1, class 2, and class 3 remote-control, signaling, and power-limited circuits.

This is a big section with not a lot of questions on it. This makes it difficult to cherry pick your keyword from the exam question. You will need to get familiar with this section so you’re not overwhelmed by the amount of redundant information.

Let’s start by looking at the very last Table in 725

Table 725.179

Here is the breakdown of what all these cable means. The most used of these cables is plenum rated and you’ll see why.

Now look at Table 725.124 you see that plenum rated cable can be used in most scenarios.

Highlight the note that says cable A shall be permitted to be used in place of cable B. Table 725.124 Cable Substitution Hierarchy


Index remote-control, signaling and power-limited circuits.

Find Separation

Go to 725.136 and Highlight:

·        ·       A General

·        ·       B Separated by barriers

·        ·       C Raceways

·        ·       D Within enclosures

·        ·       E Single opening

·        ·       F Manholes

·        ·       G Cable trays

·        ·       H In Hoistways

·        ·       I (2in)

Keep in mind the thing about this article is to prevent the spread of fire and false signals.


Fire Alarm Systems questions out of Article 760 of NFPA 70 are few.

If you are studying for your contractor’s or unlimited license you may have 5 or 6 fire alarm questions on your exam. These questions like strobe height’s and pull stations come from NFPA 72 National Fire Alarm and signaling code.

Just so you know code says strobes, horns and speakers shall be not less than 80’’ and no more than 96’’ above finish floor.

We will start at the end the same way we did for remote-control cables.

Please find in your code book Table 760.179(I).

 Here we have the cable markings and what they mean. (FPLP being the most widely used for the same reason as CL3P)

If you look at Table 760.154(A) Cable Substitution Hierarchy

You can substitute FPLP with FPLR or FPL.

Now let’s go to our index and find Fire Alarm Systems.

Find conductors.

Highlight "Copper only" in section 760.49(A)

For the last thing I want you look in the definitions for Fire Alarm Circuit Integrity (CI) Cable.

Highlight: ensure continued operation of critical circuits during a specified time under fire conditions.

Chapter 8


Any communications cable, radio and TV equipment, Antenna wiring, or Broadband communications systems running parallel with power circuits especially high voltage circuits like lighting circuits will induce voltages and currents onto the cable, producing interference that may cause problems with sensitive electronics.

In my experience the focus here should be on grounding and bonding, separation from power wires, and workman like manner.

Communications Circuits


Let’s get into some communications circuits.

Please turn to article 800 in your code book and read the definitions.

Now let’s look at Part I General section

800.24 Mechanical execution of work.

Highlight: Neat workmanlike manner

Section 800.50 Circuits requiring primary protection

These circuits that are coming over from the overhead drop to the building will require 4’’ of separation.

Highlight 4’’

Section 800.53 Lighting conductors

Highlight 6’ separation between Communication wires and lighting conductors.

Part IV

Grounding methods

800.100(A)(4)/ FPN

Make your grounding wire as short as possible not to exceed 20’ for lightning events.

Highlight 20’

800.100(D) Bonding of Electrodes

A bonding jumper not smaller than 6 AWG copper.



This is the coax cable section.

Coax entering a building 820.44(4) exception.

Highlight Not less than 12 in where it cannot be avoided.


When run on the building they coax must be separated by 4’’

Highlight 4’’


Where practicable separation shall be 6’ from lighting conductors.

Highlight: 6’

820.93 Grounding of the outer conductive shield

We have all seen the coax cable grounding block at the point of entrance to a dwelling. Where the cable is coming down from the service drop attached to the house and terminates into a weatherproof grounding block and then runs out of the block and enters the dwelling. Well the grounding electrode conductor from the block shall not be smaller than #14 AWG and shall not be required to be large than #6 AWG. Typically, the grounding electrode conductor will terminate into the intersystem bonding termination required by article 250.94.


·       800.100(A)(3), Size, 14 AWG

·       250.94 Intersystem bonding termination


Also be sure to check out Table 820.154(a) Applications of listed Coax Cables in Buildings

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Chapter 9


This is my favorite section to cover because of you get a question on tables it will be a definite win.

First please turn to chapter 9 tables and just read the Notes to Tables.


·       Annex C, max, conductors, of the same size, permitted, conduit

·       Nipple 60%

Notes to Table part (6)

This is the one guys so know this. Every electrical exam has this question.


·       Conductors of different sizes, Table 5 for dimensions, Table 4 for the conduit.

Table 2

This table is handy in the field it tells us how much conduit the particular bend is going to take up.

Table 4

This table is essential to finding out conductor fill on the exam. Let’s look at the headings of all the tables. EMT, ENT, FMC, IMC, LFNC-B, LFNC-A, LFMC, RMC, PVC schedule 80, HDPE.

If these acronyms are confusing, go to the article listed with the table and read the definitions

40% this is where you go.

You won’t be asked this, but unless they ask you about a nipple which is 60% fill or if they ask you about one conductor in the conduit which is 53% fill or any other of the things on the table like 2 conductors or total area. You will use the 40% column.

Got it good we will move on to Table 5.

Table 5 Dimensions of insulated wire.

Please look at the types of wire insulation.

RHH, RHW, RHW-2, THHN, THWN, all different types of wire insulation and remember, this table is fixture wires as well so if you can’t find the insulation, and the gauge wire in the same box just move on to the box that has it. No problem.

Example: If they ask you for the area of a 6 AWG, THHW You can find THHW on the first page of the table but not in 6 gauge. You have to look in the next section.

The book tries to help us by breaking the table into 4 sections. They list each Type of insulation covered in each section. (this is why the Types are bold above each section)

Okay so you have found your Type of wire and the gauge of wire in the same section. Which column do we get the answer from?

You are looking for the Approximate Area of the specific conductor. Whether you use mm squared or inches squared it doesn’t matter, just be sure to use the same unit of measure in Table 4. In the 40% column of course.

Example question: What size IMC (intermediate metal conduit) shall we use for 3-4/0 XHHW, and 25 #12 THHN conductors?

What the exam question is asking you to do is:

·        Calculate the amount of area of all the conductors combined from Table 5

·        then find the correct type of conduit in Table 4

·        then tell them the minimum conduit trade size that will fit your calculated area into 40%


4/0 XHHW = .3197 inches squared

3 x .3197 = .9591 inches squared

#12 THHN = .0133 inches squared

25 x .0133 =.3325 inches squared

Total calculated area .3325 + .9591 = 1.2916 inches squared

Go to Table 4 Intermediate Metal Conduit (IMC)

40% column, inches squared

The minimum trade size for these conductors is 2” because you can put up to 1.452 square inches into a 2’’ IMC


 Table 5A

If you get a question asking you to run a bare conductor with your insulated conductors, you will get the bare conductor Approximate Area from Table 5A.

Table 8

This is the table you need for voltage drop calculations. The part we are discussing is the Circular mils.

You will need to change the size or AWG (gauge) wire found in Table 310.15(B)(16) into circular mils so you can get the proper resistance of the conductor.

Basically the voltage doesn’t care about the conductor jacket or insulation, it’s all about the copper. How much copper is inside the insulating jacket?

Look at 4/0 you see how it says 211600 that is the area of copper inside the jacket. 211,600 circular mils of copper.

Now you see under the size column where it says 250? That is 250Kcmil, or 250,000 circular mils.

The size column of Table 8 shows the AWG (gauge) from 18 – 4/0 then the Kcmil from 250 – 2000

Now looking at the Table 8 do you see Stranding and below that Quantity? This shows you the number of strands per Size of the conductor.

As far as the rest of Table 8 just make sure you understand it but I don’t see you getting any exam questions on it. Use Table 5A for getting bare copper Approximate Areas. 

Annex D

Please refer to the Service Load Calculation section of

Annex E

Types of construction

Example question:

What is the maximum permitted number of stories for a rated Type III multi-family dwelling?

A.   1

B.   2

C.   3

D.  4

Answer is B. 2 stories

Please turn to Informational Annex E in your code book.

Highlight: Type III

I hope you’ve enjoyed this Study Guide and were able to study deep into your code book. If you Have any comments, please e-mail

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