Electrical - convert 110v to 220v outlet using 12/2 w/ground

You can use the existing 12/2, but you'll have to dump the outlet / light since you won't have a valid neutral, just two hots (marking the white wire with red tape as the other hot) and a ground. You could potentially use a 220V light, such a commercial fluorescent or HID unit.

Pete C.

He could also use a transformer to derive enough 110V for a lightbulb.

Or, a two-lamp fixture could be rewired in series; the white wire from each lampholder tied together would float, so the two bulbs would need to be the same wattage. (UL might not approve of this.)

Putting a 220V ballast in a fluorescent shop light might be the best option.

Bob

Your cheapest option is to simply buy 240 volt light bulbs available at most any electrical wholesaler. There are even online sources for them like Grainger, and McMaster-Carr. Ideally, the system should be properly rewired using NM 12/3 w ground in case you need to add a 120V outlet, for example, for a heater. Cheers,

Joe

Certainly.

Pretty sure they wouldn't like it since it would leave a 240v differential across a single socket with the bulb out if the power was left on when changing bulbs like many people do.

Right or a nice little HID fixture like one of the 70 watt HPS.

Pete C.

What's wrong with using the light and outlet? No worse than knob and tube...

Nick

Not a recommended practice, especially in a location like a well house. You could get a small step down transformer to power the light and outlet

Code violation. And yes, it is worse than knob and tube, because it would impose a voltage on the grounding conductor, thus energizing the entire grounding system. Not good.

Not much, and it seems equivalent. K & T has two hots and a neutral, no?

Nick

But in this case, you wouldn't have 2 hots and a neutral, he'd have 2 hots and a ground and no neutral. The existing neutral wire is being converted to a hot wire. With a few *very* specific (and obsolete but still grandfathered) exceptions, a grounding wire and a grounded wire (neutral) are not the same thing.

Bob

If you're replacing the wire you should go up to a heavier gauge and install a little six space sub panel. Minimal extra cost and much more flexible.

Pete C.

We might use the ground wire as a neutral. K & T has no ground...

Nick

Reference the original post, which stated that it's NM (Romex) cable... the NEC flatly prohibits using using the bare wire in NM cable as the neutral conductor.

So?

Nick

Nick, you asked a question and received several valid answers, all based on two things: NEC, and safety. Why ask for advice if you're just going to flaunt it

Life following art.

You and the NEC are the perfect match! ;-)

-zero

Salvaging the 12/2wg cable (are you sure it's NM and not UF?) is not worth doing the job wrong. Now if it was 10 gauge cable and there's a metal well casing in the pumphouse, it would be tempting to put in a little 30A service entrance rated subpanel and overlooking the bare wire problem.

Bob

I haven't seen any answers based on safety.

Nick

All the answers were based on safety, regardless if you see it or not

So running 240V *and* 120V loads on the same 12/2 NM cable is a Code violation.