Neutral/Grounds Separation?

[Christopher Currins]

This topic is in another thread in members only. I'd like to know electricians view (opinion) regarding this.

Isn't this always required?.......EGC's must be bonded to the cabinets, and the neutrals must be isolated from the cabinet - the neutrals must not be grounded at any point past the service equipment.


At an inspection yesterday I found this service, that was installed by a reputable licensed local electrical contractor.

4-unit building....disconnect(s) outside at meter....panels located in basement....4-wire feed....bonding strap....neutrals and grounds not separated...all 4 panels wired the same (2 examples). (Photos)

A comment in this thread by a very knowledgeable and experienced inspector was;

I see this a lot on condos, townhomes, etc. Disconnect outside by meter, but a panel in unit with its own disconnect AND the neutrals / grounds on same buss.

Local electrician or code guy DO NOT look at the inside panel as a SUB. They consider it the MAIN and the outside DISCONNECT just a COURTESY switch.

All opinions welcomed.

[Jeffrey R. Pope]

Here is the reference (as posted in the other thread) to isolated neutrals;

250.24 Grounding Service-Supplied Alternating Current Systems.

(A) System Grounding Connections. A premises wiring system supplied by a grounded ac service shall have a grounding electrode conductor connected to the grounded service conductor, at each service, in accordance with 250.24(A)(I) through (A)(5).

250.24(A)(5) Load-Side Grounding Connections. A grounding connection shall not be made to any grounded conductor on the load side of the service disconnecting means except as otherwise permitted in this article.

There may be a better one, but here is a reference to grounding (bonding) EGC's at sub panels (load-side equipment);

250.96 Bonding Other Enclosures.

(A) General. Metal raceways, cable trays, cable armor, cable sheath, enclosures, frames, fittings, and other metal non-current-carrying parts that are to serve as grounding conductors, with or without the use of supplementary equipment grounding conductors, shall be effectively bonded where necessary to ensure electrical continuity and the capacity to conduct safely any fault current likely to be imposed on them. Any nonconductive paint, enamel, or similar coating shall be removed at threads, contact points, and contact surfaces or be connected by means of fittings designed so as to make such removal unnecessary.

Originally Posted by ccurrins

Local electrician or code guy DO NOT look at the inside panel as a SUB. They consider it the MAIN and the outside DISCONNECT just a COURTESY switch.

Regardless of their opinion, they are incorrect and this condition should be reported as improper.

[Christopher Currins]

Originally Posted by jpope

Here is the reference (as posted in the other thread) to isolated neutrals;

250.24 Grounding Service-Supplied Alternating Current Systems.

(A) System Grounding Connections. A premises wiring system supplied by a grounded ac service shall have a grounding electrode conductor connected to the grounded service conductor, at each service, in accordance with 250.24(A)(I) through (A)(5).

250.24(A)(5) Load-Side Grounding Connections. A grounding connection shall not be made to any grounded conductor on the load side of the service disconnecting means except as otherwise permitted in this article.

There may be a better one, but here is a reference to grounding (bonding) EGC's at sub panels (load-side equipment);

250.96 Bonding Other Enclosures.

(A) General. Metal raceways, cable trays, cable armor, cable sheath, enclosures, frames, fittings, and other metal non-current-carrying parts that are to serve as grounding conductors, with or without the use of supplementary equipment grounding conductors, shall be effectively bonded where necessary to ensure electrical continuity and the capacity to conduct safely any fault current likely to be imposed on them. Any nonconductive paint, enamel, or similar coating shall be removed at threads, contact points, and contact surfaces or be connected by means of fittings designed so as to make such removal unnecessary.

Regardless of their opinion, they are incorrect and this condition should be reported as improper.

Appreciate that Jeff. I was typing at same you were posting that on other thread.

[Robert Meier]

Originally Posted by ccurrins

Local electrician or code guy DO NOT look at the inside panel as a SUB. They consider it the MAIN and the outside DISCONNECT just a COURTESY switch.

All opinions welcomed.

Sorry but an electrician who misses this one needs some refresher courses. An electrician should know what a service disconnect is and it's not a courtesy switch.

[Robert J. OConnor]

Originally Posted by ccurrins

They consider it the MAIN and the outside DISCONNECT just a COURTESY switch.

There is no such thing as a "courtesy switch". Jeff & Rob are right. Neutrals and grounds are connected at the service disconnect ... period. After that, neturals and grounds should be separated (unless it's a remote building panel ... like for a detached garage)

Sounds like someone is blowing some CYA smoke.

JMO & 2-Nickels ...

[Robert J. OConnor]

Originally Posted by roconnor

... unless it's a remote building panel ... like for a detached garage ...

Rob & I dont see eye-to-eye on that one though (duck) ...

[Robert Meier]

Originally Posted by roconnor

Rob & I dont see eye-to-eye on that one though (duck) ...

Actually we do, as long as those installations were permitted by code at the time it was installed and inspected.

[Robert J. OConnor]

Originally Posted by Robert Meier

... as long as those installations were permitted by code at the time it was installed and inspected.

Thats sometimes a very sticky issue, as what is written in the code and how that is interpreted/applied can vary ...

[Robert Meier]

Originally Posted by roconnor

Thats sometimes a very sticky issue, as what is written in the code and how that is interpreted/applied can vary ...

Not sure what can vary. For example, jurisdiction has adopted the 2008 NEC, it's 2011, I'm running an underground feeder to a new detached garage. I must pull in an EGC. See clear as day.

I'm sure we could dance around this all day.

[Robert J. OConnor]

Originally Posted by Robert Meier

See clear as day.

Most of the time, yes ... all of the time, no (just do a little surfing of the board at www.mikeholt.com as you probably have). Take that same garage and make it an existing feeder that improperly grounds an SE only panel with a bonded neutral, and ... well, lets not beat that one to death ...

Originally Posted by Robert Meier

I'm sure we could dance around this all day.

I'm sure we could ...

[Paul W. Abernathy]

There are some situations where a case to neutral connection is made on the load side of a service disconnect...but those are situations that are for another time. Typically on any installation constructed under the 2008 National Electrical Code the case to neutral connection would not take place beyond the service disconnect. If you run into an existing condition at a detached garage that was built prior to the 2008 NEC adoption then well....it's existing and acceptable as long as they meet the criteria listed under Section 250.32(B) Exceptions. It is very possible it was legal in the eyes of the CODE and became illegal or unsafe over time....which is where you would step in. being legal at one time and migrating to illegal or unsafe over a period of time is a different thing all together.

[Robert J. OConnor]

Originally Posted by pabernathy

There are some situations where a case to ground connection is made on the load side of a service disconnect...but those are situations that are for another time.

I assume you meant case to neutral connection there ...

[Paul W. Abernathy]

Originally Posted by roconnor

I assume you meant case to neutral connection there ...

lol....yep