Here is what you are missing about the code book!
1) Take a look at this NH Bulletin Breakdown and apply it to your Bulletin. If you would like me to do it for you email me at Jim@NECtesting.com
2) Table 310.15(B)(16) has 3 columns for ampacities of insulated conductors.
Say you are trying to find the AWG wire to feed an equipment load calculated 55 Amps. The question says the conductor is THHN. You can only use the 60°C column to find the answer. If the amperage is under 100 Amps you must use the 60° column. #6 AWG
Say you are trying to find the AWG wire to feed an equipment load calculated 155 Amps. The question says the conductor is THHN. You can only use the 75° column to find the answer. If the amperage is over 100 amps you must use the 75°C column. 2/0 AWG
If you are derating for more than 3 current carrying conductors in a raceway or derating for temperature then you are allowed to use the 90°C column for derating that is it!
3) General Knowledge questions are not in the book. Stop wasting time looking for them.
- If your trying to find the amperage for feeders you need to use Table XIV
- If your trying to find the overcurrent protection you need to use the nameplate rating