Neutral conductor

[guschash]

Where in the code does it mention only one neutral under screw at panel ? I looked in article 200 .

 

[tank728]

I believe it's a listing requirement by the manufacturer. Check the literature on the panel

 

[LarryFine]

408.41

 

[Little Bill]

To be technically correct, the rule is only one conductor under the screw on the neutral bar, not just two neutrals. It use to be common practice to put the grounded/neutral and the EGC under the same screw. I don't recall if it was allowed but was certainly done.

 

[LarryFine]

It use to be common practice to put the grounded/neutral and the EGC under the same screw. I don't recall if it was allowed but was certainly done.

It does make more sense than two neutrals.

 

[infinity]

To be technically correct, the rule is only one conductor under the screw on the neutral bar, not just two neutrals. It use to be common practice to put the grounded/neutral and the EGC under the same screw. I don't recall if it was allowed but was certainly done.

Definitely not allowed and home inspectors love to call those out.

 

[Knuckle Dragger]

Double tap!!!hmy:

 

[kwired]

To be technically correct, the rule is only one conductor under the screw on the neutral bar, not just two neutrals. It use to be common practice to put the grounded/neutral and the EGC under the same screw. I don't recall if it was allowed but was certainly done.

Did not read code, but pretty certain it is something to the effect that only one "grounded conductor" per terminal. Parallel conductors, where allowed, can land in a terminal that is designed for multiple conductors.

EGC's, if they can land there, can have how ever many the terminal is rated for.

IIRC many panels instructions only allowed one grounded conductor per terminal on typical neutral bus but did allow multiple grounding conductors. At some point (right or wrong - that is another topic) NEC decided this instruction wasn't being followed enough and decided to put it into code.

 

[steve66]

Did not read code, but pretty certain it is something to the effect that only one "grounded conductor" per terminal. Parallel conductors, where allowed, can land in a terminal that is designed for multiple conductors.

EGC's, if they can land there, can have how ever many the terminal is rated for.

IIRC many panels instructions only allowed one grounded conductor per terminal on typical neutral bus but did allow multiple grounding conductors. At some point (right or wrong - that is another topic) NEC decided this instruction wasn't being followed enough and decided to put it into code.

That's pretty much right. The handbook clarifies that this is basically for troubleshooting safety.

If 2 neutrals are under the same screw, and someone needs to disconnect one neutral for troubleshooting, you don't want to make them also disconnect another neutral for a circuit that may still be hot. So that's why it only applies to grounded conductors, and why there is an exception for parallel conductors.

 

[jaggedben]

To be technically correct, the rule is only one conductor under the screw on the neutral bar, not just two neutrals. It use to be common practice to put the grounded/neutral and the EGC under the same screw. I don't recall if it was allowed but was certainly done.

Did not read code, but pretty certain it is something to the effect that only one "grounded conductor" per terminal.

To be technically correct, it's both. Here is the code language:

Each grounded conductor shall terminate within the panelboard in an individual terminal that is not also used for another conductor.

(And then the exception for paralleled conductors.)

Strictly speaking, it does not matter if the terminal is on a 'neutral bar', and it does not prohibit multiple EGCs from landing on another terminal on the same bar if allowed by the manufacturer.

 

[kwired]

To be technically correct, it's both. Here is the code language:

Each grounded conductor shall terminate within the panelboard in an individual terminal that is not also used for another conductor.

(And then the exception for paralleled conductors.)

Strictly speaking, it does not matter if the terminal is on a 'neutral bar', and it does not prohibit multiple EGCs from landing on another terminal on the same bar if allowed by the manufacturer.

And that applies to the grounded (usually a neutral) conductor. If EGC's are permitted for any reason on the same bus, they do not have to be individual conductor per termination if the terminal accepts more than one conductor per its listing. I know Square D neutral bus bars are typically rated for 2 #14 or 2 #12. I think there are even some others out there that are listed to accept three 14 or 12 conductors - but still can only be one conductor per code if it is a "grounded circuit conductor"

Not disagreeing with you I think you just said same thing but in a slightly different way.

 

[kwired]

That's pretty much right. The handbook clarifies that this is basically for troubleshooting safety.

If 2 neutrals are under the same screw, and someone needs to disconnect one neutral for troubleshooting, you don't want to make them also disconnect another neutral for a circuit that may still be hot. So that's why it only applies to grounded conductors, and why there is an exception for parallel conductors.

One thing I think should be possibly considered is allowing multiple grounded conductors to land on same terminal (if it is otherwise rated for multiple conductors) if the associated ungrounded conductors have the same disconnecting means - including multipole or handle tied breakers.

 

[tom baker]

Its a UL requirement and was added to the NEC as it was not well known. The reason is to prevent an open neutral on MEBCs where one neutral is removed.