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Subpanel wired with common neutral and ground

Posted by whispertoo (My Page) on
Wed, Jun 19, 13 at 23:37

This is a 100A subpanel used for A/C, electric heat, and 2 other 20 A circuits. Service entrance cable was used and the bare aluminum is connected to the isolated neutral bus- and of course there is no ground. I know this has to be fixed, but running the proper new cable will be very difficult- But a single wire could be more easily managed.
My question- Is it permissible to run an insulated neutral wire outside and alongside the SE cable to the isolated bus and move the twisted uninsulated alum to a new ground bus properly bonded to the box?
If no- then how about a 10/2 with all 3 conductors twisted together to provide the missing neutral?

Follow-Up Postings:

RE: Subpanel wired with common neutral and ground

No and HELL NO.

RE: Subpanel wired with common neutral and ground

One simple correction is to use Type SER cable to completely replace the existing sub-panel feed.

RE: Subpanel wired with common neutral and ground

OK- Thanks for these replies.
One last question.
If I remove all 120V breakers and just devote this subpanel to 240 -2P loads (no neutral and thus no neutral current) does it still need a neutral wire from the main to meet code?

Here is a pic- obviously not done by a good electrician.

RE: Subpanel wired with common neutral and ground

WHOH Not done by a good electrician? Not done by an electrician at all. In addition to the improper grounding, it's only a matter of time until that piece of NM running through the naked hole wears through and electrifies that panel (hopefully tripping a breaker in the process but given the dumbass grounding procedure, there's no indication that it will happen before killing somebody).

I fear that if I had more of that picture, I'd find more dangerous, stupid, and otherwise illegal stuff going on.

Get thee to a qualified person!

RE: Subpanel wired with common neutral and ground

Yes ronnatalie, That's what I meant-
There is one other 20A cable coming in the same way lower down in the box.
Can anyone give an opinion about my last question?

RE: Subpanel wired with common neutral and ground

If there are no 120V (or other loads requiring a neutral) you MIGHT get away with it, but frankly I suspect an inspector will give you a hard time on a panel wired as such because nothing stops some unsuspecting person from adding such a load later not realizing the goofball cob job this is.

RE: Subpanel wired with common neutral and ground

We removed the subpanel and used the SE cable with a
60 A disconnect at the A/C location to serve the AC with 240V.
Changed breaker from 100A to 60 A in the main panel.
Other circuits were rewired to the main panel.
Looks better now.

Thanks to all who replied.

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