Isolated Nuetral

[csoc64]

Can someone please enlighten me as to the reasoning for separating neutrals in sub-panels. What are the consequences if they are left combined?

 

[petersonra]

Can someone please enlighten me as to the reasoning for separating neutrals in sub-panels. What are the consequences if they are left combined?

I never heard of anyone doing this. Maybe you can elaborate on what you actually mean. I suspect you actually meant to ask something other than what you did.

 

[Dennis Alwon]

I never heard of anyone doing this. Maybe you can elaborate on what you actually mean. I suspect you actually meant to ask something other than what you did.

I think the op is asking why the equipment grounding conductor and the neutrals are separated in a sub panel. That would be my guess.

 

[csoc64]

I think the op is asking why the equipment grounding conductor and the neutrals are separated in a sub panel. That would be my guess.

That is correct.

 

[petersonra]

That is correct.

Its a rule. I don't get it either since we commonly connect the service to ground at both the pole and the service disconnect.

 

[RichB]

my understanding--if I am reading the op correctly--is to ensure no neutral current on any EGC/GEC. If they were tied together at a sub-panel then you would have the potential for current to show up on any and all ground/bond wires--I think(?):?

Anyway that's my story and I'm sticking to it--until someone comes along and explains what I read wrong!!:slaphead:

 

[petersonra]

my understanding--if I am reading the op correctly--is to ensure no neutral current on any EGC/GEC. If they were tied together at a sub-panel then you would have the potential for current to show up on any and all ground/bond wires--I think(?):?

Anyway that's my story and I'm sticking to it--until someone comes along and explains what I read wrong!!:slaphead:

I think that is the answer but why it would matter all that much is another thing.

This was a common install until fairly recently.

 

[RichB]

I think that is the answer but why it would matter all that much is another thing.

This was a common install until fairly recently.

I agree---I think it was just a couple/three cycles ago they changed it

 

[GoldDigger]

I agree---I think it was just a couple/three cycles ago they changed it

The motivation, without reading the comments around the change, would seem to be twofold:
1. Keeping normal current off the EGCs on general principles and
2. Allowing feeder breakers to be GFCI without having to rewire everything.