How do you convert a 120v outlet into a 240v outlet?

Question

I am setting up a pottery studio in a detached garage and need a 240v outlet for a kiln. The garage has 4 120v outlets that are all wired to the same breaker. I cannot add any breakers without having to run another power line and would like to avoid this. Is it possible to combine two 120v outlets to make one 240v outlet? Can this be done even if both outlets are connected to the same 120v breaker? There is also another breaker for the lighting if that helps. Thanks for any help you can give, I just want to have an idea of what I am getting into before I hire an electrician.

Answer 1

This requires extensive changes for safety reasons.

The existing wire would have to be replaced with four conductor wire.

The existing wire, 120V, has a hot wire, neutral wire, and a ground wire. In a 220 circuit, there is are two hot wires, a neutral wire, and a ground wire.

If you are not able to run new wiring and install a 220 outlet, you will need to contact a licensed electrician.

Answer 2

If they're all wired to the same single pole breaker,

you've got 120V. wiring to that circuit.

You need two poles to get 240V. and you've only

got one.

Sorry.

(You've probably got 240V. wiring to that garage,

but you also probably don't have the capacity to

run a kiln. They typically draw a lot of power.

It's not only voltage, but amperage that you

need to match.)

Answer 3

Call a qualified professional electrician to do this project.  It breaks down to you will need a new wire to the detached garage, a small breaker box in the garage and then the power to the lights, receptacles and your kiln can be taken from the new box.  Otherwise, you will need to take the kiln power on a separate feed from your main panel and install an additional ground rod for the garage.  Good luck and enjoy your hobby.   Do you have gas?  A gas powered kiln may be another solution.

Answer 4

Be safe, call a pro.

Some things an amateur can handle, but NOT this.

Answer 5

you need to get the power company to do that, they will have to change the meter outside as well, the might also run you a wire, 1, any extra will have to be done by an eletrician, or a person who nows about power, and how not to get himself shocked !

hope that helps!

Answer 6

I am confused why you have a split system. It must be very dangerous. o answer the question you cannot with out

up grading you power system, for that you need an electrician

Answer 7

240 v is only half the story

how many amps do you need?   the outlet most like are wired in 12 limiting you to a 20 amp circuit

and you realize the other outlets in the room will no longer work

********************

edit

Not without running a new wire

47 amps require a wire sized much larger than used  on outlets

outlets use 12 or 14,  47 amps is a number 6, not number 8,,,,,, NM cable follows the 60 degree column  

if you have an open basement and unfinished area from panel to  new outlet location figure about $5 per foot for labor and material to run the wire

the first guy is not completely right

not all 240 needs a neutral

Answer 8

Unfortunately you're stuck with an electrician. If all the 120V outlets are wired to the same breaker, there's no way you can make a 240V outlet from that. Further, a kiln requires THICK wire, to carry the increased current (measured in amperes) that a kiln draws. If that thick wire doesn't enter your garage, your electrician must bring new wire to the garage.

But as to voltage issues alone ...

A simple check can be made if you can find where the wires enter the garage. There should be one white wire, and there may be a green or a bare wire or there may be metal conduit enclosing the wiring. If there's one black wire, that's it: you can't make a 240V outlet in the way you've asked. If there's more than one black wire, or a black and a blue or red wire, you probably can.

The voltage between a "hot" and a "neutral" is 120V. Between a "hot" and a different "hot," it's either 240V or 208V, depending on certain electrical choices your utility has made. Of course, if both hots come from the same connection, then the voltage between them is zero. By convention, ground wires are colored green or are uninsulated or the conduit is used as the ground. Hot wires are colored black, and a switched hot wire between a switch and a fixture is colored red. Otherwise, multiple hots from different legs are colored black, red, or blue.

If you have a voltage tester that's made of two wire leads and a little neon bulb (e.g. Gardner Bender GET-100A, Radio Shack 22-102, or equivalent), you can do a test. Your lighting wiring has two wires (plus a ground, which we're not discussing here), one a white neutral and one a black hot wire. If you can safely get at the light's hot wire, say by opening the switch cover and pulling out the switch so that you can touch the tester to the wire screws, you can see if the garage can have 240V. (This requires that the power be on for this test. So be careful. You may want to flip the breaker off while you uncover the switch and pull it out, then when it's in position flip the breaker back on.)

Get a polarized extension cord (plug and sockets have one prong wider than the other) and plug it in one of the outlets. Bring the other end to where the lighting's hot wire is reachable.

First, put the leads of the tester in the two slots of the extension cord socket. The tester should glow. Note how brightly it glows. This represents 120 volts' worth of lighting.

Now take the lead out of the longer slot, and (carefully!) put it on the hot wire for the lighting. [The power is live for all of this.] Observe the tester. If it glows a lot more brightly than before, you can probably use the lighting circuit with the existing receptacle circuit to make a 240V outlet. If it fails to glow, you can't.