Connecting ground to 220v 3-wire outlet

tkrussell · Sep 5, 2007, 08:22 AM

The neutral of a 3 wire dryer circuit is also the equipment ground. Before I say just use it, really need to know how this wire is connected at the panel.

If your panel has the main breaker in it,most likely you can use the neutral at the dryer outlet as an equipment ground.

If the panelboar is a subpanel, thenyou should need to relocate the neutral wire feeding the dryer outlet to the equipment ground bar in the panel.

This will render the dryer outlet useless to a dryer.

What type of panel do you have? Where is the main breaker?

I realize your probably wondering why all these questions, this should not be this hard. The reason is with the dryer circuit and outlet, the third wire is truly a neutral in combination with the equipment ground, and needs to be used as such. Once the wire is used strictly as an equipment ground, the connection at the panel needs to be confirmed, and changed accordingly.

Clear as mud?

Bbucky · Sep 5, 2007, 09:22 PM

Quote:

Originally Posted by Bbucky

I am trying to connect my bandsaw to an old-style 3-wire 220v dryer outlet (2 hot wires, 1 neutral). My bandsaw has no neutral wire. Do I connect the ground from the machine to the neutral socket?

I see. If the appliance just uses neutral in combination with ground then wouldn't it already be connected to the ground bar in the panel? I don't have a lot of experience with electrical systems.

Anyway, we are in a townhouse so we just have the subpanel. I think the main breaker is outside. What would I have to change? This is starting to get above my comfort level.

KISS · Sep 5, 2007, 10:24 PM

Take a picture of the panel with the cover removed and identify where the dryer wires enter the panel and where they connect to (written, or annotated) and we'll go from there.

tkrussell · Sep 6, 2007, 02:30 AM

The panel will need to be opened and the neutral wire will need to relocated from the neutral bar to the equipment ground bar.

Perhaps you should have a pro do this.

Bbucky · Sep 6, 2007, 06:46 PM

Here's a pic of the subpanel. I put an arrow pointing to the bar where the white wire from the dryer outlet connects.

KISS · Sep 7, 2007, 08:52 AM

Your dryer likely uses Black, red and white. Do you see where that bare wire toward the right of the bar your pointing to.

Remove the white wire from where the dryer plug connects in the panel and snug snug the screw so it doesn't work loose.

I'd suggest getting some green electrical tape and tape the white wire green at both ends. Taping it green means coloring about 1.5" of the insulation. This is in esscense a mechanism of that's used to change the color of an existing wire and there will be no confusion for others that follow.

Insert the wire in the bar where the bare is connected and tighten. Wire at the other end and your done.

The white and bare are at the same potential, 0 volts and they are connected together in the main panel.

Here is a nice illustrated photo of a main panel:

http://www.rd.com/images/tfhimport/2...g001_size2.jpg

Note, that in this panel the whites and grounds are all connected to the same bar. This is not what you appear to have.

tkrussell · Sep 7, 2007, 12:31 PM

If you decide to work in this panel I highly recommend that you shut off the main breaker that you mentioned is outside. Those large lugs at the top, one in view in the picture, is the feed from the main breaker, and is very much alive until the main is turned off.

Bbucky · Sep 8, 2007, 12:16 PM

Thanks for all the advice. Switched the wire and the bandsaw is working great!

Connecting ground to 220v 3-wire outlet

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