wiring 240v receptacle


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Old 01-07-17, 10:37 AM
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wiring 240v receptacle

Have an existing lg30 receptacle 30 amp breaker 10gauge wire that is metal cable it is used for a table saw. The outlet is too far away from the saw. I have 4wire nm 10gauge wire that I would like to use. The existing hookup to the receptacle now is 3 wire black and red to brass terminals and there is a white wire that is hooked up to the green termina on the receptaclel. The white wire goes to the main panel neutral/ground bar. Is the mc cable supplying a ground and bond at the receptacle box as well? Withe the 4wire nm cable should the bare copper go to the green screw on the receptacle and then bond that to the outlet box? Also, red and black to breaker bare copper ground to neutral/ground bar in main panel? White wire? cutoff cap off? Thanks.Name:  IMG_0382[1].jpg
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Old 01-07-17, 12:14 PM
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The existing hookup to the receptacle now is 3 wire black and red to brass terminals and there is a white wire that is hooked up to the green termina on the receptaclel.
That is wrong. A white can not be used as a ground. If the mertal conduit is continuous to the breaker panel You should jumper the receptacle to the metal box with a green (or bare) wire. The white should be capped with a wire nut on both ends and not used.
I have 4wire nm 10gauge wire that I would like to use.
The white would not be used. Cap with a wire nut on both ends. The bare ground would be connected to the ground at the original box and to the receptacle and the box if metal at the new location.

Terminology:
I have 4wire nm 10gauge
That is called 3-conductor WG or 10-3 WG NM-b. Since all modern NM-b comes with ground we often don't even asdd the "WG". It is implied.
 
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Old 01-07-17, 02:38 PM
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That is not MC cable. MC cable has an insulated ground. That looks like type AC cable.
 
 

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