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 questions:
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.
Keith
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 breaker spaces: 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....
randy
Go with #6 stranded. You can fit the four wire (hot/hot/neutral/ground) in half inch rigid conduit, so the only difference is the extra cost of the wire.
That is how I did my garage.
#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
3/4" conduit.I think I'd use #8 copper in conduit or #6 aluminum SER, and a 40A breaker.
Bob
i could be wrong but i believe code calls for 1-1/2" conduit for #6. not that you have to follow code...
randy
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 limit again.Bob
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 = .0366Total .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 good.
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.
Jake
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.
Buy a bottle of wire lube. The real stuff works a lot better than all of the things you have in the garage and it won't harm the wire.
the 'wire lube' is basically ky jelly. you may already have some handy
randy
Obviously you have never seen wire lub. I not a jelly, it is liquid. Jellly would tend to collect any dirt in the pipe and make abrasive mud.
I take it you've never worked with "Polywater?" It's *exactly* like KY jelly, only even more so!
jeez. if you need to save the rest of your ky jelly for other purposes dont take it out on me
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.
randy
I used Joy that is used for washing dishes.
Everyone I see uses yellow 77. I guess I just don't get out enough. :-).
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