I built my own 12x20 workshop and have run 8 AWG wire from the house panel into the workshop panel (complete with buried ground rod at the workshop).

At the house I could run my 220 compressor simply using a dual Breaker/pole switch. This only required one wire to each pole and a ground (no neutral connection required).

Well, this doesn't seem to work from my workshop panel. All I can get is 110v in spite of dual breaker/poles wired the same way as the house. What am I missing??

Thanks kindly for your input. Please speak simply - Ralf<><

That double breaker is that, a double breaker, isn't it and not two breakers separated from each other. If by some chance you used two separate breakers, they must be next to one another.

Maybe I am misunderstanding. Do you have 240V at the workshop panel? Is the workshop panel a split buss panel?

I had already learned (by experience) that the breakers have to be next to each other because the connection strips the breakers grab on to are not joined (they even have to be energized separately). I used 8/3 wire to the remote panel and jumbered the second breaker to energize both power strips. Everything works fine in the shop on 110 to include multiple outlets for power tools and extensive lighting. I just can't seem to get 220 power to my compressor - Ralf<><

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Originally Posted by hkstroud

That double breaker is that, a double breaker, isn't it and not two breakers separated from each other. If by some chance you used two separate breakers, they must be next to one another.

Maybe I am misunderstanding. Do you have 240V at the workshop panel? Is the workshop panel a split buss panel?

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The workshop panel is a split buss (if that refers to the separated power strips that the breakers grab on to. I assumed if I ran an 8/3 line to the shop panel and used a double breaker (with a jumper to connect them to each other) to energize the split buss, then I would have 220 available via a double breaker (2 x 110 = 220).

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Originally Posted by ralfwg

I used 8/3 wire to the remote panel and jumbered the second breaker to energize both power strips. Ralf<><

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Don't understand.

In the house you should have the two hots (black and red) connected to a double breaker and the neutral (white) connected to the neutral buss as well as the ground connected to the neutral buss. In the shop your hots should be connected to the input lugs and the neutral connected to the neutral lug or buss. The ground should go to a separate ground buss (which you will probably have to install). By 8/3 you do mean a 3-conductor (4-wire) cable don't you?

If you do not have input lugs in the shop panel you would use a double breaker there to make contact with the power strips.

Apparently what you're explaining is my original problem. In the house I was able to get 220v to my compressor by simply connecting red & black to the double breaker (no neutral or white required) and the ground contact. Therefore, I assumed (incorrectly? ) if I run a hot (black), a neutral (white) and a ground (8/3 wire) to the shop, I would have the required power. Apparently I'm missing an additional hot wire! Ralf <><

Sorry ,but you are correct that you assumption was incorrect. How's that for a double negative. Yes, you must run two hots, a neutral and a ground to the shop to have both 120V and 240V at the shop which is what I assume you want. With what you have now you can 120V or 240V but not both. 8/3 cable is 8 gauge wire with 3 conductors and a ground wire for a total of 4 wires. The ground is not a conductor, hence not counted. Sound like you ran 8/2 cable. A real bummer since its underground. In you compressor wiring you only need 240V, therefore you could use 2-conductor cable with both conductors hot. No neutral needed.

Please explain the wiring in the shop panel. If you used a double breaker in the house and connected black and white to the breaker and jumpered the breakers in the shop, what did you connect to the neutral. Again, please explain in great detail all of your wiring. I am concerned that you may have a very unsafe condition.

FWIW:

Ground and neutral bars have to be isolated in the sub panel.

Since the sub-panel location is detached, then a ground rod should at the su-panel AND ground at the sub-panel should also connected to the MAIN panel.

Okay. I'll just change the motor on the compressor to a 110v until I can run an additional hot wire.

From the house I ran a hot (black) to one breaker, a neutral (white) to the neutral bar and a ground to the ground bar in the shop panel. Because that only energized half of the panel (right side), I added a breaker next to the first one and inserted a jumper wire between the two breakers at the shop panel. This energized the other half of the panel (left side) and all of my 110v breakers work fine to my lights and outlets. Everything seems well grounded with a dedicated grounding rod to that panel. There are no hot to the touch breakers, outlets or light switches. When I use power tools and the like there is no fluctuation in amperage as indicated by steady power to tools and lights. Does that satisfy the safety concern in your opinion? Ralf <><

The wire doing the bridging should be rated at least the size of the bridgeing breaker. This is a temporary fix. You can also do this at the main lug, but don't put two wires under the screws, use a product designed to do this. It will accept two wires to one lug.

Make sure the neutral and ground bars have no connection to one another. Usually there is a green screw that needs to be removed on the neutral bar and a separate ground bar added.

Yes, thank you. You have 120V to the shop. About KISS's concern about two wires under one screw, you could wire nut a couple of pigtails onto the black and go to both breakers. Enjoy you new shop.

Thanks guys. You were a great help. At least I know things are SAFE - Ralf <><