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AssuredElectrical
AssuredElectrical, Master Electrician
Category: Electrical
Satisfied Customers: 4241
Experience:  Contractor-42+ Years in the ElectricalTrade
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How do I convert 220 volt 3 phase to 220 volt single phase

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How do I convert 220 volt 3 phase to 220 volt single phase power?
AssuredElectrical :

Welcome. My name is ***** ***** would be glad to assist.

AssuredElectrical :

Is this in a panel? Or at another location on site?

AssuredElectrical :

What exactly do you have and need?

Customer:

I have a partner coming to a trade show and needs to 220v single phase to demo a welder. Can this conversion be made at the receptacle or at the breaker?

AssuredElectrical :

Ok, have you measured the voltages at the receptacle?

Customer:

I have not personally but an electrician at the show site verified 220 volt 3 phase power to the welding outlet.

AssuredElectrical :

and the new welder just needs 240 and does not need any 120 volt?

Customer:

According to my friend (coming from Italy) all he needs is an outlet producing 220v single phase power.

AssuredElectrical :

Ok, if there is 3 phase 220 volts, all you have to do, is cap one of the phase wires. Use the 2 remaining phase wires and the ground and you will have 220 volt single phase.

AssuredElectrical :

Breaker will still trip if needed and it will work with only the 2 phases connected.

AssuredElectrical :

You can change the breaker if wanted, but not necessary for the temporary arrangement

Customer:

So this is more or less the same concept as when wiring a 220 volt circuit in entrance panel in a home.

AssuredElectrical :

Well, yes. The home gets 220 volts but also has a neutral which gives you 120 volts also, so the home is 120/240.

AssuredElectrical :

The welder would be strictly 220 volts

Customer:

Just making trying to make a comparison, like taking each of the conducting wires to the circuit and neutral to ground.

AssuredElectrical :

Not sure I follow.

AssuredElectrical :

A home gets 240 volts and a neutral, neutral is not ground

AssuredElectrical :

ground is another connection in the setup.

AssuredElectrical :

Old installations have the neutral tied to the grounds also, but no more , now they are totally separate

Customer:

In a home there are three wires coming to the entrance: two with 220 volts and one neutral. To make a 220 circuit the two 220 volt wires connect to the load & the neutral is connected to the ground strip. To make a 110 volt circuit only one of the hot wires is connected to the load along with the neutral.

AssuredElectrical :

yes, that is correct, the lines into the home are actually 120, 120 neutral. But you have it correct on the wiring. I just wanted to be sure on the neutral is a neutral and not used as a ground wire.

AssuredElectrical :

neutrals carry the same amount of current as a hot, the ground does not

Customer:

I used the wrong terminology sorry got us down a rabbit trail. So at the show just disconnect one of the three hot legs, cap it off for safety and the outlet will function normally but on single phase 220.

AssuredElectrical :

That is correct, I am sure there is aground there also which most likely is needed as well.

Customer:

OK thanks

AssuredElectrical :

you are most welcome, glad to assist. Good luck at the show.

AssuredElectrical and 2 other Electrical Specialists are ready to help you