I am installing a subpanel in my woodshop. I need at the minimum a 30
A circuit. The run from subpanel to shop is less than 50 feet so
voltage drop is well within tolerance.
I was thinking of pulling either 6 or 8 gauge cable and I have two
1) Would you use 6 or 8 gauge or stick with 10 gauge?
2) Is 6 or 8 gauge a pain in the butt to work with at the main panel?
Also, any war stories on your panel installs would be appreciated.
there is only one main panel. thats the one near the meter. im assuming
you have the first case, but just in case im covering both...
if you have no power to the garage and are installing a subpanel:
the cost of getting better wire/panel/breakers to handle more power is
nothing compared to the cost/labor/hassle of rewiring it and 30A is NOT
enough. 60 would be a minimum and 100 preferable. i just did my garage and
the cost of doing a 100A panel vs a 30A panel was 0 labor, and 60$ in parts.
if you already have power to the garage and need another panel for more
if its the second case and you just need more breaker slots, i'd run 8
gauge. is it going to be a pain bending the wires? well its going to be
less of a pain than undoing 10 and installing 8 later anyway....
#8 wire is the easiest size to work with because it is made of small
strands so it's flexible; I think you can run four 8 guage wires in a
1/2" conduit, and EMT and plastic conduit are both easy to work with.
The next easiest would be #6 SER without a conduit. #10 give you the
worst of both worlds because it is a big solid wire, and you might have
too much voltage drop.
If you use #6 wires, don't try to cram them in a 1/2" conduit, go with a
I think I'd use #8 copper in conduit or #6 aluminum SER, and a 40A breaker.
I know you can use 3/4" for three #6 THHN/THWN wires. You might have to
go up to 1" for 4 conductors if they are all #6, I don't know. I think
the raceway fill chart says four #6 "compact conductors". You certainly
don't need 1-1/4" or 1-1/2" even if you're using old rubber-insulated wires.
You don't necessarily need #6 for the neutral or the ground of a
240/120V feeder circuit, the NEC allows one size smaller. Two 6's and
two 8's would fit nicely in a 3/4" conduit. Three #6's and a #8 ground
wire ought to fit in a 3/4" but it's getting kind of close to the upper
Here's my calculation (again by memory...but close 'nuff)
# 6 THHN .0507 in(2) area each. 3 required for 2 legs and Neutral.
#8 THHN .0211 in(2) area each. 1 required for Ground.
3 x .0507 = .1521
1 x .0211 = .0366
Total .1887 used area
Now, for Rigid Conduit with more than 2 wires, you are only allowed 40
percent of the internal diameter of the conduit (.220 for 3/4"). You're
Run the rigid, pull the 6's and 1 #8 and you'll be fine.
I like the Square D stuff, so look at that closely. As previously said,
wiring in this size must be stranded. That makes it easy to work with.
Please don't use aluminum, though. Copper THHN is safe, reliable and not
much more than the aluminum crap.
Anyone who believes the conduit fill tables has not pulled much wire. This is
the max allowed, not what you can pull through any significant length of pipe
or one with a couple of bends in it.
If you are really thinking about getting close to the max, be sure to have
plenty of access points along the way so you can pull this in short stretches.
Once you price out conduit bodies you will just go with bigger pipe.
jeez. if you need to save the rest of your ky jelly for other purposes dont
take it out on me <g>
sorry couldnt resist.
such a product does indeed exist. it worked very well too. although at the
end i was reaching for the wire and it slipped, sort of fell over, and
completely slimed me. that wasnt so cool.... in any case im sure there
are many types of wire lube.
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