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#112933 - 11/29/01 09:29 PM Disconnect Bonding
Webmaster Offline

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 Quote:
This is the secondary disconnect for the transformer in the other post ( Here ). (also removed) Note the two grounded conductors under one lug. This is now a violation in the '02 NEC. I am not sure if it was a UL listing violation or not at the time it was installed 12 years ago. Something else that is unorthodox. The conduit on the right comes from the transformer. Note the EGC loops through both ground bushings while the one coming out of the other conduit goes directly to the can. To each his own I say

-Nick



[This message has been edited by Webmaster (edited 11-30-2001).]

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#112934 - 11/30/01 07:16 PM Re: Disconnect Bonding
resqcapt19 Offline
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Registered: 11/10/00
Posts: 2209
Loc: IL
Is this really a violation of the new rule in 408.21 requiring individual terminals for grounded conductors in switchboards and panelboards? Is a fused disconnect within the scope of Article 408? Also even if the disconnect is within the scope of 408, is this really two grounded conductors? It looks a like a splice in a single grounded conductor to me. There still may be an issue if the terminal isn't listed for use with two conductors, but I don think it is a violation of either the letter or intent of 408.21.
Don(resqcapt19)
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#112935 - 12/01/01 07:48 AM Re: Disconnect Bonding
Nick Offline
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Registered: 08/13/01
Posts: 603
Loc: Riverside, CA
Good point Don.
Let me see if I have this straight. The reasoning behind the rule is if someone were to lift a neutral in a panelboard that was doubled up with another there would be a hazard of causing sever voltage imbalance at down stream loads, right? 408.21 only applies to switchboards and panelboards, Right? 408 does not cover disconnecting means making this an acceptable installation. (The lug is duel rated.) Lets say, hypothetically, that the load end of this feeder lands in a panelboard where it continues on to another panelboard via either a breaker or a bus tap. Now lets say the where the grounded conductors come together in this first panel from the disconnect and the sub panel, they are landed under the same lug. Would be a violation of 408.21 or not? How would this be any different electrically than the situation shown here? For that matter, what if this were a panel instead of a disconnect. It would then be a violation? Or is it not because it is a splice. Where do you draw the line in calling it a splice and two separate conductors?

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#112936 - 12/01/01 09:14 AM Re: Disconnect Bonding
resqcapt19 Offline
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Registered: 11/10/00
Posts: 2209
Loc: IL
Nick,
With a feeder grounded conductor, there is no reason to have the same rule as for branch circuit grounded conductors. If the feeded grounded conductor is lifted you have lost the grounded conductor for the feeder circuit and have created a problem for any multiwire branch circuits fed by that feeder. The same thing happens if there are two terminations as would happen with only one termination. As long as the termination is listed for 2 conductors, I see no code or real problem with making a feeder grounded conductor in that way.
Don(resqcapt19)
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#112937 - 12/01/01 09:02 PM Re: Disconnect Bonding
Nick Offline
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Registered: 08/13/01
Posts: 603
Loc: Riverside, CA
Forgive me; I don’t have the ’02 code yet.
I understand and agree with your reasoning here Don but is that what the letter of 408.21 says? Does it distinguish between branch circuit and feeder neutrals?

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#112938 - 12/02/01 06:48 PM Re: Disconnect Bonding
resqcapt19 Offline
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Registered: 11/10/00
Posts: 2209
Loc: IL
The letter of the new rule applies to all grounded conductors in panelboards.
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#112939 - 12/10/01 08:20 AM Re: Disconnect Bonding
Nick Offline
Member

Registered: 08/13/01
Posts: 603
Loc: Riverside, CA
If the new section does not distinguish between branch and feeder, would you find this installation a violation or not? The lug is rated for the two conductors. One comes from a transformer the other goes on to another panel.

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#112940 - 12/10/01 10:18 AM Re: Disconnect Bonding
resqcapt19 Offline
Member

Registered: 11/10/00
Posts: 2209
Loc: IL
Nick,
I would call that a violation. If you lift the neutral wire going the other panel, you will create an open neutral for both panels.
Don(resqcapt19)
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