Another question about a Neutral in a 230 Circuit

Re: Another question about a Neutral in a 230 Circ

John K Jordan

I cap unused wires with a wire nut, leaving enough wire in the box for future use if necessary. Do not ground.

Re: Another question about a Neutral in a 230 Circ

Mark Nowicki

" So that I can use the same outlet as an adjacent tool, I am using a NEMA 14-30 4-wire outlet, and a 4-wire cord with matching plug. "

I don' understand this part.

4-wire

Mark Mandell - Gone Round In New Jersey

Running a 240 circuit with 4-wire (2 hots, a white common/neutral, and a ground) allows you to either split the feed into two 120v feeds or maintain the main 240v but take a 120 aux receptacle off the side using one hot and the common. The common is capped in the box when not used. Examples are a feed for a 240v lathe or band saw coupled with one or more accessory work lights using 120v or an outlet for a 120v power tool like a drill or sander.

PS: This NOT the way to get two 120v circuits by pulling a single cable. Proper way is to run separate 3-wire cables off of separate breakers. If you establish the 120v aux receptacle, make sure that the 240 breaker is one that will trip the entire circuit if there's a short in the 120v feed.

Cap it...

John in NM

The only place that the neutral (white) wire should be grounded is at your service panel.

Re: 4-wire

Mark Nowicki

To eliminate the need for the red ink I would pull two wires, one for the 240V and another one for 120V each protected by its own breaker.

Re: Another question about a Neutral in a 230 Circ

Wayne

You can use a 3 wire cable and only connect the two hot terminals and the ground

Agreed

Thanks

Stephen Roth

Thanks for the help.

To clarify some issues that my help others, here is some more detail....

I have a number of 230V 30 amp tools that are on mobile bases. There are a plethora of outlet configurations for 30 amp plugs. Since many 230V tools come without a cord (probably for this reason), I thought it would be easier to have a consistent outlet/plug configuration around the shop for my 30 amp tools. That way I can move the tools around without extension cords. (FYI, each outlet is run to a separate 230V 30 Amp breaker, although the odds of running two tools at the same time are very low.)

The problem is that some tools (like SawStop) have a 4 wire configuration at the tool, and others (like the Powermatic) have 3 wire. I assume SawStop needs the neutral for the 120 electronics (as Mark mentioned).

So I end up with a extra neutral wire that runs to the Powermatic. Even though it is not needed, I thought there could be some advantage to ground it. Apparently not, so I will cap it.

Thanks for all the advice.

Re: Cap it...

Stephen Roth

Thanks!

Re: 4-wire

Bill Howatt

Why do you say this in "Not the way...". This is a multi-wire branch circuit and is legal but requires a double-breaker across the 2 different hot lines and the neutral is to be connected with a cap - not using 2 of the neutral screws on the receptacle.

Bill

Not The Way

Mark Mandell - Gone Round In New Jersey

in the context of the OP's description of using a single breaker (bridged) for the circuit. If two, completely independent, breakers are used, I agree there's no problem, but that's not what he was describing for his usage.

I actually use a 4-wire feed for my lathe with a branch aux 120 receptacle but it's a GFCI and will trip long before the main 240 pops so the circuit is safe.

Re: Not The Way

Ed Wozniak-Buffalo, NY

Mark,

I would expect your GFCI to trip only if there is a ground fault. It should not trip due to an overload condition.

True, But

Mark Mandell - Gone Round In New Jersey

the aux receptacle is only used for light loads like a fan, a mini spotlight, or a corded hand drill for power sanding turnings.

When I sell this place, this and several other circuits will be removed so I'm not worried about someone abusing the set-up later.