OT: electical sub panel grounding

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On Sat, 11 Oct 2014 09:31:01 -0700, "Lew Hodgett"

Wrong. Ground bars are *not* insulated/isolated from the case. Neutral bars are and strapped when necessary.

Yes, but you're still wrong.
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On Sat, 11 Oct 2014 11:35:40 -0400, snipped-for-privacy@snyder.on.ca wrote:

Ground "isolated" from the neutral, not from the case. It is screwed right to the case.
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On Sat, 11 Oct 2014 16:24:33 -0400, snipped-for-privacy@attt.bizz wrote:

Nowhere did he say what you say he said. He said: Insulated neutral busses ---- and ground busses mounted and wires only as described --- will meet those NEC requirements.
He did not say: Insulated neutral bus and ground bus bars --- mounted and wires ONLY as described --- will meat those NEC requirements.
So no, he was NOT wrong.
You just chose to read it wrong.

And so are you - - - - in the interpretation of what he wrote.
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On Sat, 11 Oct 2014 22:34:47 -0400, snipped-for-privacy@snyder.on.ca wrote:

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Wrong. "INSULATED neutral buss and ground buss bars" means the both are INSULATED (the symmetry of the phrase indicates such). Since he refuses to clarify...

That's *exactly* what he did say. It may not be what he meant but it's what he said.

Perhaps he wrote it wrong but since he refuses to clarify...

You must be illiterate.
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Actually it does. If you read the NEC you'll find several instances where multiple grounds are described. In general every building is allowed to have a ground.
What the NEC cares about is having only a single path for the neutral (which they occasionally call the "grounded conductor", just to make things confusing).

I cannot find this wording in the NEC(*), at least not in section 250.30, which I think is the relevant section for subpanels. All that that section specifies is that the neutral on the subpanel be isolated (and it does say isolated, not insulated).

It definately does, and no-one is disputing that. However I think your source is going beyond the NEC, and is perhaps looking at a specific situation rather than the general case (in particular, I think it's looking at a situation where the ground is tied to the neutral, and the neutral is bonded to the case. In that situation to use the panel for a subpanel the tie between neutral and ground and the bond to the case must be removed, and a new bond between ground and case added).
John
(* 2008 handbook, I don't have access to the 2014 edition).
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I think we're getting confused here. How many pieces of copper are in the feed? 3 or 4?
A second wire, outside the feed, is connected from panel to panel as a ground, right?

Puckdropper
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On 08 Oct 2014 21:04:39 GMT, Puckdropper

4 L1, L2, N and Grnd

A fifth wire, if you want to be accurate., or a second ground.

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On Wed, 08 Oct 2014 19:22:39 -0400, snipped-for-privacy@snyder.on.ca wrote:

With N and G only tied together in one place, at the entrance panel (which may not be either of the two panels).
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On Wed, 08 Oct 2014 19:28:03 -0400, snipped-for-privacy@attt.bizz wrote:

Which in his case, according to the initial post, IS the main panel (and way back when, USED to be the sub panel - which means the sub panel may or may not be a legally allowed sub-panel. If it had the main braker or fuse in the panel, there is a STRONG possibility the neutral and ground are permanently bonded (does not have a removeable jumper)) Some of those panels CAN ge hacked or modified to separate the neutral from the ground - some can not easily be modified. (and if it is truely "modified" it is no longer an approved electrical device, so again it is not code compliant - so we will ASS U ME this is a compliant insulated(or isolated) neutral panel.
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On Wed, 08 Oct 2014 19:33:45 -0400, snipped-for-privacy@snyder.on.ca wrote:

The post was confusing. Not sure exactly what he has but the point is still valid. It's possible that none of these panels are the "entrance". They haven't been in either of my last houses.

The separate ground bars are available for many of these boxes. I agree, though, it sounds like they may not be wired so they're separable. They can be rewired (if the parts are available for the boxes).

Hacking, of course, wouldn't be allowed. The boxes and all hardware have to be listed for the purpose. These parts are often available, though.
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On Wed, 8 Oct 2014 22:39:32 -0400, "Mike Marlow"

Not sure of current panels, but entrance panels (those with the main breaker built in) a few years back often did not have the bonding screw, while panels manufactured without the built-in main breaker (separate - not taking up a "load" slot) most often did have the removeable bonding screw.
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And that's a Code violation AFAIK.

Yes, he was. AFAIK, anyway.
If you want a definitive answer, repost this in alt.home.repair, titled "PING: gfretwell re subpanel grounding". Greg (?) Fretwell is a licensed electrician who is a regular in that group, and whatever advice he gives you, you can take to the bank.
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OK, I will try to be more clear.
I have a three conductor with additional ground conductor cable going between panels. In the main panel, fed from the road, the neutral and grounds are equal, with the normal configuration of the neutral and grounds bonded to the panel frame, and the whole thing grounded to a ground rod and to the neutral coming in from the pole.
In the sub panel, which was the house's original panel, the neutral is not bonded to the frame of the panel, and there is a separate grounding lug connected and bonded to the frame of the panel.
Now for what the cable coming from the main panel is connected to. Remember that it is two hot wires (insulated) a neutral wire (insulated) and grounding wire wrapped as individual strands around all of the insulated conductors, and all of it covered in plastic sheathing. The two hot wires are of course connected to the two breaker busses, the neutral is connected to the insulated buss bar and has all of the neutrals coming from the house circuits connected to it. The buss bar that is bonded to the frame has all of the ground wires from the circuits going to it, and is connected to the ground wire in the service feed cable.
This additional ground wire the inspector wanted was to be a #6 bare copper wire connected at the main panel (service entrance) onto the ground/neutral buss and then run to the sub panel and connected to the ground buss. (which is bonded to the frame)
I believe Clair read my description correctly, and that the two #6 bare copper and the ground conductor in the cable are connected to the same things in each panel, and they are parallel, and that the #6 is indeed above code and unnecessary.
If it is necessary, I sure would like to know the reasoning behind what it does, and why it is necessary.
OK, go at it!
--
Jim in NC


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No, not fired on account of this case. Probably the same stuff that got him fired, though. I never protested, but I also got off with only promising to put the #6 in, and never did install it. Now, I am bringing everything up to code and want to know what the code says about his extra wire.
What is this ground loop thing? I think that an extra wire connected to the same thing on both panels as the ground wire in the cable would put them in parallel, just like adding extra size to the cable ground conductor, not a loop.
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Jim in NC


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"Doug Winterburn" wrote in
Didja use the black gunk (anti-oxidant paste) on all the aluminum wire panel connections?
You betcha. I payed attnson to all the sparkys I was around! I think mine was green, though.
I was pretty sure this inspector was full of it. I never installed the extra ground, and that was years ago. No problems. I ws just trying to do everything exactly to code, and wanted to check for sure. I think it is safe to say consensus was reached saying the second ground wire is not necessary, and some have said it could be a violation or harmful.
I will go without it and sleep easy.
Jim in NC
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Yep. That is how it is.


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"Puckdropper" <puckdropper(at)yahoo(dot)com> wrote in message

4, but they are aluminum. Two hots and a neutral, all three insulated, with additional bare conductor.

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On 10/08/2014 10:20 PM, Morgans wrote:

Didja use the black gunk (anti-oxidant paste) on all the aluminum wire panel connections?
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Correctly designed panel with a insulated lug for neutral with a connector screwed onto the frame and into the holes in the lug and tightened down. All I had to do is add a non insulated buss for the all of the grounds and remove the bonding connector.
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Jim in NC


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Which is exactly my beef. This guy wants an additional #6 outside the feed.
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Jim in NC


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