FIRE RATING of electrical room

[hohlthomeinspections]

Can someone tell me if and where in the NEC it is required to have a 1 hour rating from the electrical room that seperates it from the rest of the building? This is for a commercial structure. I have been advised it is in the NEC but cannot locate it. Thanks for your help

 

[ryan_618]

If you are talking about a less than 600V installation, see 450.21(B), but note that most transformers meet the criteria of EX No. 2.

 

[ron]

I agree with Ryan.

 

[cowboyjwc]

I agree also. Other than that there is no requirement for the room to be rated.

You also must remember that to get a one hour rating it is simply 5/8 drywall, a 2x4 and 5/8 drywall. Most commercial walls are one hour simply by the way they are constructed. The only concern you would have is your penetrations.

 

[rich123]

a one hour fire rating is required if there is a transformer rated 225kva or more

 

[iwire]

a one hour fire rating is required if there is a transformer rated 225kva or more

See the exception Ryan mentions

If you are talking about a less than 600V installation, see 450.21(B), but note that most transformers meet the criteria of EX No. 2.