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Ross
Subpanel Q’s
Ross

Just moved into a new house!  I just finished installing a 6 slot sub-panel in our attached garage for electric car charging and my table saw and dust collector, etc.  My master electrician good friend recently passed and he was the one I ran everything by so I guess y’all get that privilege now :)

100A service homeline 

50A breaker in main panel

6ga (2 hot, neutral and 8 ga ground) in 3/4” EMT (1936 house has plastered basement ceiling so I’ve had to do the run under that) 23’ run

In subpanel...

40A breaker for level 2 car charger (car will be pulling closer to 29A)

20A GFI X2 for power tools

15A GFI for garage doors

Questions... do I bond the neutral and ground at the sub-panel?  I can purchase another bus bar for the box if needed.

Online wire calculators give me max 50A current with 25’ of #6, but I’m Reading people going higher than this on 80 feet?  Am I missing something?

Thanks in advance!

 

 

HandyAndyInMtAiry
Re: Subpanel Q’s
HandyAndyInMtAiry

Ross,

That is quite a load on a 100 amp panel. It all depends on your local code. But code or not, I would drive a ground rod for that sub-panel. You cannot use the same bonding bar for ground and neutral wires. You should never do that, especially with the AFCI\GFCI devices. They will not work correctly.

I am one that will always go a few steps above what is listed in code. I never want to follow the minimal. There is nothing wrong with going above that level to larger or better. Things like an electric dryer on a 30 amp circuit is required to have a number 10 AWG. I pulled number 6 AWG. It puts less stress on the entire system. After switching our main service from 60 amp service to 800 amp service, our monthly electric bill has dropped.

I bet that was a tough pull thru 3/4" conduit. I would have used 1.5" just to allow the wires to keep a more constant temp in the pipe. If there is no room in the pipe for air to circulate, the heat created by the current load and everyday outside temps have no places to go.

Andrew

Handy Andy In Mt Airy NC

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