Moving Circuits to Subpanel - 300.3B Debate

[Greentagger]

Appears the intent is for grounded conductors and ungrounded to originate from same panel per language in 300.3(B) and 300.3(B)(4).??

 

[ActionDave]

Appears the intent is for grounded conductors and ungrounded to originate from same panel per language in 300.3(B) and 300.3(B)(4).??

I bet most electricians have never seen a column width panelboard I know I haven't except for pictures, but I think the language of 300.3(B)(4) gives weight to the argument that there is no reason to extend the neutrals in the situation described in OP.

 

[Tulsa Electrician]

I can say in response to the feeder neutral being used for the purpose of the branch circuits is not compliant in this case.

200.6

What I see as an issue is that at some point some one may tie a new 120v branch circuit to that panle. They will see single pole breakers and and use it. Them what run the grounded conductor over to other panel or just tie it to the ground bar. If it was all two pole 240v loads like is done for HVAC equipment and no netural bar in panle with a lable then I would be ok with it.
I would never do it. I feel if the panel has netural loads then the feeder should have a grounded conductor ran with the feeder.
When you have a feed through two section panle the grounded conductor is ran to section two and the grounded conductors are connected to that netural bar to which the branch circuit originated.

Playing devil's advocate here, let's say we have a two section panle set side by side with a nipple between them. If we do what the OP has done we can omit the grounded conductor of the feeder going to section two and use that % of raceway fill to run branch circuits to section one through the same raceway as feeders then from section one out to source. After all section one netural buss is rated for 100% of the load.

I bet most electricians have never seen a column width panelboard I know I haven't except for pictures, but I think the language of 300.3(B)(4) gives weight to the argument that there is no reason to extend the neutrals in the situation described in OP.

I may self have never seen one and only recently learned about them. The one item with them is there is a through to the netural section. it is also an listed assembly.

My final thought is just because it can be done should I. Consider the installation method to the application.

 

[roger]

What I see as an issue is that at some point some one may tie a new 120v branch circuit to that panle.

Why would that be a problem? There is a neutral feeder conductor in the new panel connected to it's neutral bus.

 

[Greentagger]

300.20(A).

 

[roger]

What does that have to do with it? There is no inductive heating in this installation, the feeders and branch circuits negate any net currents.

 

[Greentagger]

What does that have to do with it? There is no inductive heating in this installation, the feeders and branch circuits negate any net currents.

Everything? That’s what it says?

 

[roger]

Everything? That’s what it says?

Where do you see any inductive heating being caused if the feeder current negates the branch circuit current?

 

[kwired]

Everything? That’s what it says?

AFAIK the rule was primarily written to prevent inductive heating, but maybe not worded well enough to indicate that. Some the conditions in the following subsections however do indicate this is the main reason for the rule.

 

[petersonra]

I can say in response to the feeder neutral being used for the purpose of the branch circuits is not compliant in this case.

200.6

But if you don't run any of them...

 

[Greentagger]

All the language in 300.20? Word for word.

Where do you see any inductive heating being caused if the feeder current negates the branch circuit current?

 

[roger]

All the language in 300.20? Word for word.

Where do you see any inductive heating being caused if the feeder current negates the branch circuit current?

Go back and read post #2 and tell me where or how that is not allowed. In this case the branch circuit neutrals are not being used in the nipple.

 

[infinity]

Electrically you don't need the neutrals run with the ungrounded conductors into the sub-panel because there is no inductive heating. However I don't see how not running them complies with 300.20(A).

 

[roger]

Electrically you don't need the neutrals run with the ungrounded conductors into the sub-panel because there is no inductive heating. However I don't see how not running them complies with 300.20(A).

IMO , the wording "where used" covers it. If the grounded conductor is not necessary (not being used) in a raceway it is not needed. If there were no other means of negating currents then I would say it is necessary.

 

[infinity]

IMO , the wording "where used" covers it. If the grounded conductor is not necessary (not being used) in a raceway it is not needed. If there were no other means of negating currents then I would say it is necessary.

I've always interpreted where used to mean if the circuit actually has a neutral, like a 120 volt circuit. For a 208 or 240 volt 2-wire circuit it is not used.

 

[Greentagger]

But the grounded conductors are required in this circuit. It is a single phase 120V circuit? IMO . “All phase conductors “ could be interpreted as a 3 phase or single phase 240V circuit, without a neutral?

 

[Greentagger]

I've always interpreted where used to mean if the circuit actually has a neutral, like a 120 volt circuit. For a 208 or 240 volt 2-wire circuit it is not used.


Me too. Sorry was typing on top of you.

 

[roger]

I've always interpreted where used to mean if the circuit actually has a neutral, like a 120 volt circuit. For a 208 or 240 volt 2-wire circuit it is not used.

Then that would mean switch loops would include them.

 

[roger]

But the grounded conductors are required in this circuit. It is a single phase 120V circuit? IMO . “All phase conductors “ could be interpreted as a 3 phase or single phase 240V circuit, without a neutral?

Then once again, how could we do as stated in post #2.

 

[roger]

OK, I'll give a hint to the answer to my question, 404.2 Exception but, if the breakers are being used as switches this allows not installing the neutral in a raceway.