90a #2 aluminum

[Petey156]

Does anyone know the NEC number that says branch circuits using #2 aluminum can only be on a 90 amp breaker vs a 100 amp breaker?

No code book at my house and could not find it online

 

[Speedy Petey]

It's not one particular code section number. A few sections apply to this.

Why do you ask?

 

[wyliesdiesels]

Books at the shop. If u really want to know i can look it up tomorrow!

 

[JCByrd24]

90A is the rating of the cable normally. There is an exception for residential service (main only not sub) that allows 100A because it's close enough and residences rarely run at full load and even more rarely at any significant duty cycle. I don't have the reference, but you are searching for it backwards, this info might help you find it.

 

[alfredeneuman]

It's a Table --- Article 310.15 (B)(16)

It lists the ampacities of all the conductors between #18 and 2000KCM

And the figure at 75°C for a #2 Al is 90Amp.

 

[Petey156]

Thank you

 

[Petey156]

We have a commercial customer that did his own sub panel work in a restruant and the building dept revoked his occupancy permit, until he gets an electrical permit / inspection . He wants a list of everything I found wrong and the NEC # explaining it. The guy did nice work , only a few small thing wrong.

1. No plastic bushings
2. No separated ground bar in sub panel
3. #2 2-2-2-4 SER cable on a 100 amp breaker. Sub panel is homeline or eaton, I thinks the lugs are 75 degree.

 

[Charles (in GA)]

Prior to 2011 code that table was numbered differently than the cite in post#5 above, just so you know. It was 310.16 in the 2008 and earlier code.

Charles

 

[wyliesdiesels]

It's a Table --- Article 310.15 (B)(16)

It lists the ampacities of all the conductors between #18 and 2000KCM

And the figure at 75°C for a #2 Al is 90Amp.

Thats the ampacity table. I know some of that by heart. I thought he was wanting to know the code that allows 100a in limited circumstances...