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#5441 11/20/01 01:50 AM
Joined: Feb 2001
Posts: 32
G
Member
I know that some panel's say that this is allowed but I am against it. Two grounding conductor's is fine under one screw but two grounded conductor's under one screw will not work for me..I was putting this out there to see the response. " whyrag "

Joined: Oct 2000
Posts: 2,749
Member
See the 2002 NEC, 408.21 Grounded Conductor Terminations.


[This message has been edited by Joe Tedesco (edited 11-22-2001).]


Joe Tedesco, NEC Consultant
Joined: Jan 2001
Posts: 1,044
Tom Offline
Member
Gary,

I've not seen many panels that allow two grounded conductors under one screw. if you run across one & you only do one screw-one wire, more power to you since you have exceeded the minimum requirements of the NEC.

Wish I could have made the message icon a BIG thumbs up. Always glad to see a job that is better than the minimum.

Tom


Few things are harder to put up with than the annoyance of a good example.
Joined: Oct 2000
Posts: 5,392
S
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I'm having a bit of trouble with 408.21 EX , what is parrallel conductors in ref to?

Joined: Aug 2001
Posts: 599
N
Member
Sparky,
Isn't that parallel runs as in 310-4?I would assume that because parallel conductors are considered electrically as one the hazards associated with disconnecting them when under one terminal goes away.

Joined: Oct 2000
Posts: 5,392
S
Member
yes, ok...well it would be for bigger conductors. Let's say we have the the usual #12's etc, in a residential panel Is this cycle the end of placing a grounding & grounded ( N&G) under one screw? [Linked Image] If so, will panel listings that allow this change?

Joined: Oct 2000
Posts: 2,749
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Some of the exceptions to 310.4 could be considered also.


Joe Tedesco, NEC Consultant
Joined: Jan 2001
Posts: 1,044
Tom Offline
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Got my new code book last night & I see that 2 neutrals under one screw is pretty much a thing of the past.

Now, if they would just eliminate 2 eq. grounds under 1 screw, I wouldn't have to worry about straining my eyes on all that tiny print.


Few things are harder to put up with than the annoyance of a good example.
Joined: Aug 2001
Posts: 7,520
P
Member
I never looked that closely at panels while over there. Are most neutral busbar terminals the type where the end of the screw clamps down onto the wire inserted in a hole, or do they have flat plates clamped down on the wire by the screw like most receptacles?

Sparky:
I don't have a problem with the common neutral/ground busbar, but I'm not sure I like the idea of using the same screw for a branch cct. N & G. If the N & G stay connected firmly together (twisted maybe?) but the connection to the bar works loose while an appliance is connected the "ground" on that cct. is going to float right up to 120V. [Linked Image]

Joined: Aug 2001
Posts: 599
N
Member
Sparky,
According to Mike Holt this has been a UL listing requirement for many years. 408.21 is just making this a NEC requirement too. This way all of us in the general masses, who can’t afford to buy all UL’s literature, are aware of it’s existence.

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