# Another Garage Subpanel Q....



## Mach1 (Aug 4, 2007)

About a year ago, I wired my attached garage with a subpanel.  My sub in the garage is only 15 feet or so from the main.  I used 4 AWG THHN 90C for both hots and netrual, 6 AWG bare stranded for the ground.  The conductors are installed in 1.25" PVC 90C rated conduit.

The table I looked at when I bought the wire said #4 was good for 95A (w/90C insulation)  My breakers are the Cutler-Hammer BR type.  Since there was no 95A breaker avaliable, I used a 100A.

In hindsight, I'm wondering if using the 100 Amp BR  this was the right thing to do?  Should I switch it to a 90A breaker?  The only reason I can think of to change it to 90A would be because of de-rating due to conduit fill.  Can someone help me out? 



TIA,
Mach1


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## Parrothead (Aug 4, 2007)

Derating isn't an issue here, since there are only three current-carrying conductors in the pipe. However, the wire you used is only rated for 95 amps, and they are protected by a 100- amp breaker. to make it legal, you're going to either have to up-size the wire to #3 or down-size the breaker to 90 amp. 

BTW, since this is a subpanel, did you make sure to remove the bonding jumper in the subpanel??? Just a thought.


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