Bare wire as neutral

[Icculus]

I have a guy telling me to use 10/2 for a dryer. Black as a hot, white as a hot, bare as a neutral, with no EGC. I know this is wrong, but I'm having trouble finding the code reference. I told him it was a violation and he argued with me about it, so I'd like to be able to show him in black and white straight from the NEC. He wants to do the same thing with the range with 8/2.

 

[LarryFine]

No, no, no! Bad boy! (just kidding) Welcome to the forum.

You need to learn how to use the NEC, so I'll just you it is in Art. 250. Also, look for "keywords" in the index.

But, you're correct. The neutral and the GEC must be separate conductors, and the neutral must be insulated.

In a new installation, you must use a 4-wire circuit, and receptacle and cord if plug-in, as you would a sub-panel.

 

[Carultch]

I have a guy telling me to use 10/2 for a dryer. Black as a hot, white as a hot, bare as a neutral, with no EGC. I know this is wrong, but I'm having trouble finding the code reference. I told him it was a violation and he argued with me about it, so I'd like to be able to show him in black and white straight from the NEC. He wants to do the same thing with the range with 8/2.

It can be inferred from two other rules. 250.4(A)(3) requires bonding the housing of the device, and 250.24(A) doesn't allow the connecting the neutral to the EGC or housing once on the load side of the service disconnect. The neutral and EGC need to both be present, and remain isolated unless otherwise required by the NEC.

Dryers use the 120V for powering the motor, and the 240V (or 208V) for powering the heating elements. There will be current on the neutral, and it needs to remain on the neutral. The jacket of a multiwire cable is for mechanical protection purposes, and not electrical insulation purposes.

 

[Little Bill]

It used to be done and was legal. It changed some years ago and new installs are prohibited from only using 3-wires with the neutral also serving as the ground. That is a key point, the EGC was never allowed to be the neutral, it was the neutral that was allowed to serve as the EGC and bonded to the frame. Old installs that were done when it was legal are "grandfathered" in and can remain. Likewise with just an appliance replacement you can still use the 3-wire. But any new install requires a 4-wire receptacle and plug.

 

[Icculus]

Thank you!

 

[Greentagger]

250.142(B) is what you’re looking for.

 

[curt swartz]

It used to be done and was legal. It changed some years ago and new installs are prohibited from only using 3-wires with the neutral also serving as the ground. That is a key point, the EGC was never allowed to be the neutral, it was the neutral that was allowed to serve as the EGC and bonded to the frame. Old installs that were done when it was legal are "grandfathered" in and can remain. Likewise with just an appliance replacement you can still use the 3-wire. But any new install requires a 4-wire receptacle and plug.

It was ok to use the bare neutral of type SE cable as the grounded conductor if it originated in the service panel. It was never ok to use the bare EGC of NM cable as the grounded conductor.

 

[Little Bill]

It was ok to use the bare neutral of type SE cable as the grounded conductor if it originated in the service panel. It was never ok to use the bare EGC of NM cable as the grounded conductor.

That was my point in saying the EGC was not allowed to be the neutral. I didn't mention bare but probably should have. I do know the rule for SE cable. My guess is the SE was allowed and not the 10-2, because the EGC used to be smaller in NM than the ungrounded conductors.