Wire question

[RVA-Jeff]

I want to run a sub panel to a shed. Want to send 240v out there.

I have a 250' roll of 10/2 wG UF that I've had forever (paid for when copper was cheap).

Can I lay two lines of it to the shed, twist white and bares together then connect them to sub, then use blacks (one taped red) for the hot feeds?

 

[Stuart in MN]

The short answer is no, it's not allowed to parallel #10 wires.

 

[eljefino]

What do you want to do, run a welder? Some welders don't require neutral, so you could run a 240 branch circuit with one cable, not even on the subpanel, and another 120-only subpanel with the other cable.

Just what size is this "shed"?

 

[Charles (in GA)]

What do you want to do, run a welder? Some welders don't require neutral, so you could run a 240 branch circuit with one cable, not even on the subpanel, and another 120-only subpanel with the other cable.

Just what size is this "shed"?

Nope, he should not do that. Code only allows one circuit to a detached building. He can run one four wire, 240 circuit to a subpanel or (three or four wire) to a single receptacle in the building, or he can run one 120 circuit for lighting and receptacles, but he cannot run both.

Charles

 

[pattenp]

Well...actually he can do that if he doesn't care about code.

Nope, he cannot do that. Code only allows one circuit to a detached building. He can run one four wire, 240 circuit to a subpanel or (three or four wire) to a single receptacle in the building, or he can run one 120 circuit for lighting and receptacles, but he cannot run both.

Charles

 

[RVA-Jeff]

It is just a shed. I want to feed a small subpanel but it needs 240v in order to supply both sides so all 4 breakers can get juice.

It's possible too that I would want to send power towards the house with a generator.

I would like to be able to use the wire I have.

I would like to not burn anything down.

 

[Charles (in GA)]

Well...actually he can do that if he doesn't care about code.

Nope, he should not do that. Code only allows one circuit to a detached building. He can run one four wire, 240 circuit to a subpanel or (three or four wire) to a single receptacle in the building, or he can run one 120 circuit for lighting and receptacles, but he cannot run both.

Charles

There, fixed it for 'ya.

Charles

 

[Charles (in GA)]

It is just a shed. I want to feed a small subpanel but it needs 240v in order to supply both sides so all 4 breakers can get juice.

It's possible too that I would want to send power towards the house with a generator.

I would like to be able to use the wire I have.

I would like to not burn anything down.

The code issue is that code wants only one circuit supplying a building, no matter how large or small, just one feed. If you have multiple feeds, someone working on it will trip a breaker and think he has killed the power to the building, and then get electrocuted when he hits the other, live circuit. It might not happen till after you have moved on, or are "dead and gone" but it can easily happen, and you are setting up a trap for someone else in the future.

Charles

 

[Alchymist]

It is just a shed. I want to feed a small subpanel but it needs 240v in order to supply both sides so all 4 breakers can get juice.

If all you want is 120v circuits, simply jumper the to hot lugs in the sub panel and feed 120 on the #10. Note that you will need the ground and neutral separated i the sub-panel, and an additional ground rod system at the sub-panel.

It's possible too that I would want to send power towards the house with a generator.

Don't even think about this - wrong on several levels.

I would like to be able to use the wire I have.

Use it as described, 30 amp breaker in the main panel.

I would like to not burn anything down.

.....

 

[nehog]

It is just a shed. I want to feed a small subpanel but it needs 240v in order to supply both sides so all 4 breakers can get juice.

Yes, you can do it, but as mentioned it doesn't meet code. IOW, if you are willing to risk the issues of code violations then it is ok. Othewise just buy new wire.

It's possible too that I would want to send power towards the house with a generator.

No, nope, never, not a chance, and etc. Do not consider dual purposing that line for a generator. Not only does it not meet code, it is grossly unsafe.

I would like to be able to use the wire I have.

Craigs List it and sell it? Yard sale it? Flea market sell it? Use it to wire the inside of the shed?

I would like to not burn anything down.

In that case, yes buy new wire, and forget the 10/2 that you have as a feed. And forget back feeding that generator, get a proper transfer switch, lockout, or whatever is necessary, but don't try to back feed from another building--there are no ways to do it that are either safe or allowed by code.

 

[RVA-Jeff]

Thank you all, very helpful.

I was wondering if a jumper to supply other side would be OK. I alsp understand need for ground rod and seperate ground/neutral.

I will drop idea of generator back feed.

 

[VHF]

I think a jumper would be OK as long as your total loads at the shed don't exceed 30A at 120V. But don't stick two wires under a screw that is only designed for one.

 

[Aceman]

You can have straight 240v out there with no neutral. Or 120v, take your pick.

 

[RVA-Jeff]

If I use the 10/2 wG for 240v with no neutral, then the sub panel in shed isn't really a sub panel. No seperate neutral and ground (and no ground rod). Mark the white as red and that's it. Correct?

 

[Alchymist]

If I use the 10/2 wG for 240v with no neutral, then the sub panel in shed isn't really a sub panel. No seperate neutral and ground (and no ground rod). Mark the white as red and that's it. Correct?

If it "isn't really a sub panel", then what is it? And you still need that ground rod.

 

[RVA-Jeff]

Thought definition of subpanel was non-bonded (seperate) neutral and ground. If no neutral, then sub panel basically becomes an intro point to feed circuits that happen to be switched (breakers). Will add ground rod fosho tho.

 

[Aceman]

It's a sub, just without a neutral. So it gets wired exactly the same, rods, main disconnect, etc etc.

 

[pattenp]

If you feed a panel that is used to serve other circuits then it is a secondary panel or what is referred to as a sub-panel. The only way to use the 10/2 to the shed and be NEC compliant is to run it as a 240V single circuit or as 120V single circuit or to a 120V only secondary panel. If you want the panel to serve both 120V and 240V circuits then you need to use 10/3. A secondary panel installed in an outbuilding has to have a grounding electrode such as ground rod(s).

Edit: Or a 240V only secondary panel. That thought was sparked by Aceman's reply.

 

[Alchymist]

Ya know, the code is pretty clear on this stuff - all the weaseling going on here won"t change the facts. Calling a rose by any other name is still a rose. Me begins to think ..........Troll?

 

[pattenp]

You can't fault the guy for trying.

Ya know, the code is pretty clear on this stuff - all the weaseling going on here won"t change the facts. Calling a rose by any other name is still a rose. Me begins to think ..........Troll?

 

[RVA-Jeff]

Troll? Geez, thanks.

 

[Alchymist]

Well, I didn't actually call anyone a troll - but - reread the thread - lot of flip flopping around on how to get around the limits of what's there - advice was given, another scenario presented, more advice, another.....oh well -