[OP]
Member
Hi,
I am pulling a 20A 220V outlet for the a SawStop PCS 3HP. I am using 10GA wires and already have the 1/2 EMT attached to the wall. I am changing my mind and want to add another 20A 110V outlet close to the 220V outlet. Can I run 3 10GA and 4 12GA together in a 1/2 EMT?
Thanks
Mike
Contributor
First thing, why are you running 10 ga for a 20 amp circuit? Look up multiwire branch circuits. You could do both 20 amp 220 and 20 amp 110 on same circuit. Before someone chimes in, remember the feed into your house is a multiwire circuit. Two hots and neutral furnish both the 110 and 220. Ground is there to protect you.
[OP]
Member
I thought the 10 GA wires are better and in case I need to change the 20A to 30A later if need to. Are you saying that I can have 2 outlets, 1 with 220V and 1 with 110V on the same breaker with 2 hot and 1 ground going to the 220V and split 1 hot and ground plus neutral going to the 110V?
Thanks
Mike
Member
I'm fairly sure that 3 10 ga. and 4 12 ga. exceed the limit for 1/2" conduit. I believe 5 12 ga. wire are the limit for 1/2" conduit.
John
Member
Is the limit based on the physical size or the heat dissipation? I am wondering if the neutrals count towards the limit since they do not carry any current, therefore they do not produce any heat.Originally Posted by John McClanahan
Steve
Member
You already have a 3hp SawStop that will last you the rest of your life. So it is not something you should ever need to upgrade to a 30-amp circuit in the future. You are better off just sticking with the 12 ga wire.
No, the 10 ga wires are not necessarily better, because they are a major pain in the neck to deal with in a junction box when you don't need to.
[OP]
Member
Hum. My electrician cousin gave me a roll of MC 12ga wire which has 4 cables inside and he also put in the 20A breaker for me in the sub panel and showed me where to connect the wires and told me that 12ga should work for the 13amp draw by the Sawstop, but when I got to HD to buy the receptacles, the guy at HD said I should never use the 12ga wire for 220V. This was why I thought I can run the 10ga wires with 20amp breaker and can upgrade to a 30am in the future if I really need to and use the 12ga MC wire my cousin gave me for the 110V. I guess I can return all these 10ga wires and save myself 100 bucks.
Member
Well, the guys working at HD don't have a clue, and are the worst source of information--even worse than the internet.Stick with the 12 ga wire. It suits your needs better than anything else.
You are free to do as you please, but I will always try to steer someone toward reality versus foolish decisions based on misinformation. The notion that all 240-volt circuits needing to be 30-amp is one of the worst cases of misinformation running rampant on the internet.
[OP]
Member
Thanks Rick. I guess I'll stick with the MC 12ga wire and return the 10ga and save 100 bucks.
Member
As I understand, it has to do with heat. It's possible to get more wires pulled through, but against code. The neutral wires count. They carry the same current as the hot on a 120v circuit.
John
That was certainly bad advice from that particular HD employee, but to imply that all HD electrical department folks are inept is a gross overstatement. Often (admittedly not always) our local HD has licensed electrical contractors working that aisle and can give you sound advice. Same for the plumbing department. Can't say the same for the local Lowe's. But if you already know enough to spot a pro maybe you don't always need their advise. Yea, wiring 10 ga is a pain. Heck, wiring 12 ga is a pain after working on 15 amp circuits and 14 ga romex.Well, the guys working at HD don't have a clue, and are the worst source of information--even worse than the internet.
Last edited by Ole Anderson; 12-01-2013 at 4:54 PM.
Guest
Same here, our local HD has a retired electrician that works there quite a few hours. Very helpful guy when I can't remember how many circuits I can squeeze into a single box (for example). He also knows where stuff is when it isn't where you would expect it to be.
Member
If you Google 'conduit fill table' you can get an idea based on the code. Code allows 9 12 ga wires in a 1/2 conduit as long as it's EMT. I'm not sure of the rules here for linking, but, again, if you Google 'raceway fill calculator' you'll get a link to an automatic calculator. That calculator shows that you are just under the code for fill % for a 1/2 EMT with 3 10 ga and 4 12 ga.
However, more than code, have you ever tried to pull that amount of wire through 1/2 conduit? It's a major PITA. Unless you do this often, you might find it very difficult to pull that much wire. Even 5 or 6 12 ga wires in 1/2 conduit can get tight. Any kinks in the wire will cause it to jam even on straight runs. How many corners do you have? Are you running to junction boxes at the corners, or are you going to try to navigate that amount of wire through Ls? Just for ease of installation, I'd go up to the 3/4. It's not that much more money, though if you have the conduit already on the wall, it's a little more work. Still, though, you don't know frustrating until you've tried to fish wire through a rather full conduit.
Member
Yea like Patrick mentioned, can you stuff that much is more like what you are after. I would recommend anyone needing electrical answers to pick one of these up http://www.amazon.com/Uglys-Electric.../dp/0763790990 lots of good stuff in one of these little books. More than the average person would probably need. Would also wait until the 2014 edition comes out.
Member
No you can't. You cannot take a 120v circuit and run it off a two pole breaker. If you want a 240v, 20A circuit and a 120v, 20A circuit, they must each be run off separate breakers. And you cannot share wires either. In the OP's case, he'll have to run the feed to the saw separate from any 120v circuits.
Mike, as far as wire fill, for #12 THHN, you can pull nine (9) wires in a 1/2" pipe. So pull (3) #12 for the table saw, (4) if they require a ground and (2) #12 for the convenience circuit. Your conduit acts as a ground so unless your local code and/or the equipment requires otherwise, no need for the ground conductor. You won't have any problems with that setup.
Posting Permissions
