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I have a 4 wire supply wire. It has a black, white, red and ground wire. I want to supply a 3 wire outlet.

Do I combine the white and ground wire?

ArchonOSX
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wayne
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  • In general the black and red are going to both be hot, and you shouldn't attach the bare ground wire to the white neutral. Where is the supply coming from and what is on the other end? – Comintern Feb 24 '15 at 00:10
  • For reference, the ground (bare or green) wire is not counted when describing wires. For example, a "14/3" wire has 3 conductors (typically red, black and white) plus ground, all of which are 14AWG. A "12/2" has 2 conductors (white, black) plus ground, all of which are 12 AWG. The wire you described is a 3-conductor wire, so it will likely be a 14/3 or 12/3. – gregmac Feb 24 '15 at 01:59
  • Likewise, normally if someone says "3 wire outlet" I would think a 4-prong 240V stove or dryer plug, but in this case I'm not sure exactly what you mean, eg: a standard 120V receptacle or a p3-prong dryer outlet](http://i.stack.imgur.com/rHbwr.jpg) or similar. Is there a double-pole breaker feeding this circuit? Is it a kitchen, garage, or workshop area? It's common to have a receptacle in those locations split with each half on its own circuit, to handle multiple high-current appliances and tools. – gregmac Feb 24 '15 at 02:02

1 Answers1

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No, you absolutely should NOT connect the grounded (neutral) conductor to the grounding (earth) conductor.

If you have two ungrounded ( hot ) conductors, and you only want to use one. You can simply cap the unused conductor using a twist-on wire connector, or similar device.

However, when two ungrounded conductors are run, there's almost always a reason. It could be a simple multi-wire branch circuit, where one of the conductors is meant to feed other devices. Or it could be a multi-wire branch circuit, where one of the ungrounded conductors is switched. The latter is common where receptacles are split to allow half to always be hot, while the the other half is switched.

ArchonOSX
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Tester101
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  • There's also the possibility that there's a >20A breaker on it, which makes a regular receptacle illegal to put on this circuit: see Table 210.21(B)(3) for details. – ThreePhaseEel Feb 24 '15 at 04:53