Exam prep question

[BobbyBJr]

Hello,
I am going through Mike's Electrical Exam Preparation based on the 2002 NEC and have a question. On page 200 the question "What size conductor is required for a 104A continuous load that is protected with a 150A breaker? The answer is given as 1 AWG taken from the 75 C column. My question is how should I have known to choose the 75 C column? The other selections were 1 AWG and 2 AWG which would have worked if taken from the 90 C column.

thanks,
Bobby

 

[haskindm]

Look at 110.14(C)(1) Termination Temperature Limitations. Unless you know that the termination ratings are higher you must assume 60 degrees for under 100-amps and or AWG 1 conductor, and 75 degrees for over 100-amps and/or AWG 1 conductors.

 

[BobbyBJr]

Thanks. Upon rereading it, it is right there. Duh!!

thanks again,
Bobby