240v 20A Receptacle four wires only places for 3 wires.

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  #1  
Old 04-01-13, 11:49 AM
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240v 20A Receptacle four wires only places for 3 wires.

When using plastic junction boxes there's no real need to ground them. So what do I do with the ground wire?
The Outlet I'm concerned with doesn't work. Here's how I wired it. 12-3 W/Ground from panel. In the plastic junction box I have the red wire to one side and the black wire to the other side of the 20A receptacle. I joined the bare ground and the white neutral and took one common wire to the green screw on the receptacle. Was that wrong?
I sent another set of wires down line to another receptacle about 12 feet away and that one functions fine. I thought I wired them the same. I'm finally debugging this one that doesn't work because I'm doing another project and I figured I'd fix this one now. After opening it up everything looks good. I don't know what's wrong.

Edit, I just went and powered the panel and my newly installed GFCI 240v 20A breaker kicks out as soon as I energize it.
 
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  #2  
Old 04-01-13, 12:08 PM
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For your application ...... you would connect the bare/ground wire to the receptacles.

The white neutral wire would not be used and should not be connected together with the ground. Cap off the white wire.
 
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Old 04-01-13, 12:09 PM
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A straight 240V circuit doesn't need neutral. For that type of circuit, a three-slot receptacle can be wired as hot/hot/ground, and the neutral capped off.

Some 240V appliances need a 120/240V circuit, often for 120V controls. For a cord-and-plug connected load, a 120/240V circuit needs to be wired with a 4-slot receptacle and a 4-blade plug.

Tech Note 1: The grounded conductor (the neutral) and the grounding conductor (the ground) are bonded together at the service entrance. They should not come in contact with each other at any other point in the system.

Tech Note 2: A metal box which is bonded to ground is a safer enclosure than an unbonded plastic box for electrical splices and devices.

Echo... [SUB]Echo...echo[/SUB]
 
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Old 04-01-13, 12:15 PM
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I joined the bare ground and the white neutral and took one common wire to the green screw on the receptacle. Was that wrong?
Wrong and very dangerous. The ground should never be connected to neutral. Shut off the circuit breaker till you can remove the neutral and cap it off. You only needed 2-conductor cable not 3-conductor because this a 240 volt receptacle. 3-conductor is used on a 120/240 receptacle.

In the U.S. you remark the white of the two conductor cable red or black or any color but gray or green on both ends both tape or marker pen or paint. (In Canada you use cable intended for 240 volts that has red and black, no white.)
 

Last edited by ray2047; 04-01-13 at 02:25 PM.
  #5  
Old 04-01-13, 12:55 PM
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Ray....what were you replying to? Was something moved?

OOPs my clipboard pasted out of order. I've corrected it.

Thanks.
Ray
 

Last edited by ray2047; 04-01-13 at 02:27 PM.
  #6  
Old 04-01-13, 12:57 PM
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Hi

Thanks for all the valuable information. I'll cap off the Neutral wire in the first two boxes.

This 20A line will support 3 different receptacles. No 1 & No 2 are both two conductor outlets (Leviton 5461-W 20-Amp 250-Volt NEMA 6-20R, 2P, 3W for 3HP Table Saw). I'm glad I did it this way with the 12/3 w/gnd back when I did it. Because now at the end of the line I'm adding a new receptacle (LEVITON 2410, 20A 125/250V TWIST LOCK RECEPTACLE) So I'll need to maintain the neutral wire's integrity to satisfy the requirements of the 2410 receptacle. The 2410 will supply the power to the Brew Panel mentioned in my GFCI post. The two receptacles prior to the 2410 supply power to my 3HP Cabinet Saw and 3HP Planer.
So if I just string the neutral wire through the first two boxes and connect it on the 2410 will I satisfy all the requirements?
 
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Old 04-01-13, 01:54 PM
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So if I just string the neutral wire through the first two boxes and connect it on the 2410 will I satisfy all the requirements?
So long as your planer and saw don't need a neutral, that should be fine.
 
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Old 04-01-13, 07:03 PM
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The neutral and ground conductors being connected together, as in post #1, is what was tripping the GFCI.
 
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