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View Full Version : Convert 220 VAC 1Phase to 2-110VAC circuits


MHH
Nov 26, 2006, 10:09 AM
I have a 220VAC single phase 30 amp circuit that I would like to split into two 110VAC circuits. The 220VAC circuit has 3 wires and if I measure across the two main terminals I get the 220VAC and if I measure between a main terminal and what appears to be ground, I get the 110VAC. If I take one of the wires from one of the main terminals and what appears to be the ground of the 220vac circuit then how do I get a ground for the newly created 110VAC? Can I run a separate ground from another VAC 110 outlet and connect to the new 110VAC circuit?

Thanks

labman
Nov 26, 2006, 10:58 AM
You should have a black, red, white, and bare or green. If so, you can do it using the white as the neutral for both circuits. It is a shortcut I don't like, but OK by code.

tkrussell
Nov 26, 2006, 01:16 PM
Be sure you understand Labman correctly, he is using the proper terminology, you need a neutral AND a ground. You only mention "ground".

If the "ground" wire you have is insulated, then it can be used as a neutral. If the wire is bare it can only be a ground.

What Labman is referring to is to share a Neutral wire with two 120 volt circuits, which is allowed, but does have issues, we can get into later.

What I need from you is detail on the "ground" wire you have. Don't mean to be nitpicky, but there is a huge difference between Neutral and Ground.

Neutrals are currect carrying conductors, and if this is not correctly, or if you do not understand, you can end up sending current through-out your electrical system's grounding.

Running another wire from another outlet is never allowed. Especially if your not sure what you are running , either a ground, or a neutral.

Where are you located?

What type of cable is this wiring?

Is the "ground" insulated or bare?

I do not believe you have enough information to continue with what you are proposing until we get more detail from you.

MHH
Nov 26, 2006, 07:08 PM
Thanks for the quick responses. I checked again and unfortunately it is only a 3 wire cable for the 220VAC circuit. It has a white, black and a bare ground in a orange shield. This is what has thrown me as I was expecting a 4 wire cable for the 220, two hots , a neutral and a ground. I haven't done a voltage or continuity check from the ground of the 220 and a 110 circuit to see if there is voltage between the two or if they are indeed both at ground potential. Before I did any thing I wanted to see what the experts had to say. Thanks for all the help



Be sure you understand Labman correctly, he is using the proper terminology, you need a neutral AND a ground. You only mention "ground".

If the "ground" wire you have is insulated, then it can be used as a neutral. If the wire is bare it can only be a ground.

What Labman is referring to is to share a Neutral wire with two 120 volt circuits, which is allowed, but does have issues, we can get into later.

What I need from you is detail on the "ground" wire you have. Don't mean to be nitpicky, but there is a huge difference bewteen Neutral and Ground.

Neutrals are currect carrying conductors, and if this is not correctly, or if you do not understand, you can end up sending current through-out your electrical system's grounding.

Running another wire from another outlet is never allowed. Especially if your not sure what you are running , either a ground, or a neutral.

Where are you located?

What type of cable is this wiring?

Is the "ground" insulated or bare?

I do not beleive you have enough information to continue with what you are proposing until we get more detail from you.

Swigo
May 15, 2018, 01:05 PM
I have a 220 vac line going to a GFI box for my hot tub. I want to tap off one side of my 220 vac in the box to go to a new outlet. I plan on connecting the 110 vac to either the Black wire or the Red wire Plus the White neutral wire and the Bare wire. (all before the GFI breaker.) I will then install a GFI on my 110 vac outlet.
Does that sound right?
Thanks,
Dennis

ma0641
May 15, 2018, 03:04 PM
NEC requires a dedicated circuit for a spa/hot tub. Any outlets located at the spa must be on a separate GFCI circuit.

Stratmando
May 18, 2018, 09:36 AM
You need a Neutral AND Ground. Ground is Not to carry Current, If you did have a ground and Neutral, a Red and Black can Share a Neutral(a Multi Circuit), they need to Be Next to each other on Panel, Opposite phases, on a 2 Pole Breaker.
Being on opposite phases, If 1 circuit draws 20 amps, and other draws 15 amps, the Neutral carries the difference(5 amps), if they were on same phase, Neutral would carry current of both(35 Amps)