grounded and grounding conductors

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jaggedben said:
We just had a thread on more or less the same thing.

The NEC requires one neutral per terminal. It does not prohibit two EGCs per terminal, but the listing/panel label has to allow that. Panel labels these days usually say it's only allowed for EGCs, if they say it.
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Could a panelboard theoretically exist that is formally listed and labeled otherwise for two neutral (grounded) conductors under the same screw? And would this article of the NEC override using it that way?
 
Panelboards in the uk are listed for two neutrals under one set screw and two grounds under one set screw..but on different bars... bars here are often numbered as well, so you put the wires on bar in same order you put the breaker on it’s bar.. breaker two has its neutrals on position two and it’s grounds on position two...
 
Carultch said:
Could a panelboard theoretically exist that is formally listed and labeled otherwise for two neutral (grounded) conductors under the same screw? And would this article of the NEC override using it that way?
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We do not terminate neutrals on a panel board, we terminate them in a bus or lug.

And no bus is listed for two separate circuit neutrals under one screw.
 
Carultch said:
Could a panelboard theoretically exist that is formally listed and labeled otherwise for two neutral (grounded) conductors under the same screw? And would this article of the NEC override using it that way?
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I think someone once mentioned that listing requirements were that each terminal on the bar only to have one grounded conductor landed on them. This wasn't always happening so NEC stepped in by adding this rule. Many bars were designed to accept multiple conductors, some even will take three conductors per instructions, but listing and now NEC only want one grounded conductor per port.
 
Carultch said:
Could a panelboard theoretically exist that is formally listed and labeled otherwise for two neutral (grounded) conductors under the same screw? And would this article of the NEC override using it that way?
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Good question, I don't see how it could be listed that way in the first place but the NEC has no provision to allow it as an exception.
 
GoldDigger said:
Although as long as the EGC is the one for the same circuit as the neutral, opening one branch breaker will remove the possibility of current (and therefore voltage) on either of the conductors.
As a theoretical matter of safety I would not want to work on the EGC for a circuit without deenergizing that circuit first. As a practical matter, I might be tempted to do it, but would not admit doing it. :lol:
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Consider a 208Y/120, or a 480Y/277 panel with single pole breakers. Turning off only one circuit will not remove the possibility of power on the neutral. And opening that neutral could be costly. No?
 
joebanana said:
Consider a 208Y/120, or a 480Y/277 panel with single pole breakers. Turning off only one circuit will not remove the possibility of power on the neutral. And opening that neutral could be costly. No?
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It depends on whether or not you have MWBC's with shared neutrals. If not once the SP breaker is switched off there is no hazard in removing the circuit neutral.
 
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