ECN Forum Forums Code Related Discussion NEC & other Code issues Correct wire size

I think you will find most breakers over 30a are rated at 75c. There is no point most of the time with 30 or less because of 240.4(D)

I agree that most breakers 30A and over are rated 75 degrees, but the original post said he could not find the markings saying that. Which refers you to 110-14(c)1 for circuits rated(based on breaker size) 100 amps or less to use 60 degree column in T310-16. Now in all likelyhood, the terminals are 75 degree, but I say if the terminals aren't identified for 75 degree, then that section must come into play. strictly speaking.

Trekkie I am still not following you, the post states a minimum circuit ampacity of 110 Amps. 110 amp equipment has without a doubt 75 C terminals.

Lets say I have a 90 amp breaker that the terminals are marked 1/0 but not marked as to temperature.

Would you agree that this breaker has 75 C terminals?

Bob

I agree that a breaker marked with the wire size (#1AWG or larger) by association, is listed for 75 degree. The problem is the orginal post stated no markings. I am just saying that, without any markings at all, the terminals are based on 110-14(c)1+2. which is based on breaker size or wire size, but the terminals are unmarked, so we go with circuit(breaker) size as the manufacter sets. I am not sure why they are fusing a 110 MCA at 100 amps(max breaker), but they are the manufacuter, and they must have had to send it to UL or something to market the product. I don't doubt that they aer 75 degree terminals, but strictly speaking without evidence of what the terminal is suited for, 110-14 comes into play.