Thread: Conductor Ampacity
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Old 04-23-2008, 01:50 PM
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Bob White Bob White is offline
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Re: Conductor Ampacity
Quote:
Originally Posted by Wendell Swedberg View Post
ICC test question:

Number 12 AWG THHN , copper conductors that are located in the attic and are part of the NM cable. The ambient temperature around the conductors will be 110F. The terminal devices are not rated for more than 60degrees C......What is the conductor ampacity for this condition?

A) 20
B) 26
C) 30
D) 35

I get 30 amps from table 3605.1.....the answer is B, 26 amps...what gives?

Thanks as always for your help.

Wen
Section E3605.2 sez that for ambient temperatures other than 30 degrees C (86 deg. F), mutiply your table 3605.1 allowable ampacity by th correction factor in table 3605.2 (0.87).

30 * 0.87 = 26.1 ......
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