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Mike G.
Mike G., Master Electrician
Category: Electrical
Satisfied Customers: 7589
Experience:  Proven Professional 48 years Experience
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Here. I would appreciate if you can help me resolve a issue

Customer Question

Hello Kevin,
Michael here. I would appreciate if you can help me resolve a issue I am facing with city inspector.
I have installed UA4311-0PGP gangmeter sub panels for 8 apartments.
There are three disconnects from main supply , since it is more than 6 feet.
Inspector says, we have to isolate neutral and ground on gangmeters, how to achieve this?
Submitted: 1 year ago.
Category: Electrical
Expert:  Kevin replied 1 year ago.

Hello and welcome to Just Answer. My name is ***** ***** I will be happy to assist you with your electrical question.

1) Can you provide some additional details as to the layout? I need to understand how the meter cans are wired?

2) Are the meter cans located on the exterior or interior of the building?

3) What are you using for a "means of disconnect" after the meter cans? A high amp fused or non-fusible disco switch or a circuit breaker?

4) After the meter cans and/or "means of disconnect", you have panel boards that are configured as a sub-panel, is that correct? Are the individual panel boards a main breaker or a main lug type? Or are the "means of disconnect" located upstream of the meter cans?

5) Is the inspector requiring the neutral bonding isolation at the panel boards or at the meter cans or at the disco switch?

6) Based on the UA4311-OPGP on a link found at Home Depot, these are not sub-panels. They are Landis & Gyr meter sockets.

As you can see from my questions, I'm trying to understand the layout of the components.

Let me know what you have in place and we can take it from there.............Thanks...........Kevin:)

Customer: replied 1 year ago.
2) Interior in the building
3) before the meter cans there are two disconnectors and after meter cans there is one disconnect a high amp non fuse circuit.
4) after meter cans there is one high amp disconnect for each apartment because the distance between apartment and meter can is more than 10 feet. The sub panel is located in the apartment. Like this we have 8 meters and 8 sub panels in the apartment.
5) the inspector requiring neutral isolation from disconnect, meter can and all the sub panels. Except service main disconnect.
6) that's correct these are multi gang meter cans.
Expert:  Kevin replied 1 year ago.

Thank you for the replies and confirmation.

1) The apartment panels are configured as sub-panels and not as a main panel disconnect. Therefore, the neutral conductor from the feeder circuit to the sub-panel need to be isolated from the sub-panel metal enclosure. In order to have an isolated neutral at the sub-panels, the main bonding screw or main bonding jumper strap is NOT installed at the apartment sub-panels. On the sub-panels, only white neutrals will land on the main neutral bus bar and never any equipment grounding conductors. The sub-panels will require a separate equipment ground bar to land any equipment grounds. On a sub-panel, never intermix white neutrals with equipment grounds. Thus, separate bus bars are required for the neutrals and all equipment grounds.

2) The neutral to ground bonding only takes place at the service disconnect and never at a downstream sub-panel. The neutral needs to be bonded to the Grounding Electrode Conductor at the disconnect as well as at the meter.

Hope this helps………If you have any additional questions, let me know and I’ll be glad to answer them for you.

Otherwise, don’t forget to rate me before you log Off.

The next time you have an electrical question, you can also request for me at: ……….Thanks…………..Kevin!

Customer: replied 1 year ago.
Hey Kevin,
I think the inspector treating meter cans and disconnects as sub panels that is the rwason he wanted neutral and ground isolation at these areas..
I will explain you more clear, we have main service entering to the building at one location and there is immediate disconnect box with fuses is there, and the meter cans are installed 10 feet far from service entrance and before meter cans there is one more disconnect box installed with fuses. There is one high amp circuit is installed after meter can non fused.
The inspector is treating all of these boxes as sub panels..
second disconnect box, meter cans and gutter as a sub panel and he wanted neutral isolation from second disconnect. The sub panel in the apartment is having neutral isolation from box and ground.
My question is are these meter cans, second disconnect and gutter is considered as sub panel?? He is telling after main disconnect all the boxes are considered as sub panel.
Expert:  Kevin replied 1 year ago.

1) Yes, the inspector is correct. NEC does not specify the distance from the service entrance conductors "point of entry" to a main disconnect. NEC only states "as close as possible" from the point of entry to a main disconnect . Typically most inspectors will allow a 5 or 6 foot run from the point of entrance to the main service disco switch. Any other panels after the main disco are considered as sub-panels where the neutrals and grounds need to be isolated.

Customer: replied 1 year ago.
Can you please let us know how to isolate neutral from multi gang meter cans. Thank you
Customer: replied 1 year ago.
I have added the image of the gang meter sub panel
Please let me know what needs to be done
Also inspector is not happy with isolation kits for neutral and ground and he asked us to get a manufacturer letter to isolate.
And Siemens who manufacture these gang meters informed us that they are for service entry installation .
Amy help or advise is greatly appreciated
I can send u arch diagram if needed
Expert:  Kevin replied 1 year ago.

Thanks for the picture.

1) You mention that you installed an isolation kit? Where is the iso kit located? I am unable to see it on the picture provided?

Customer: replied 1 year ago.
We did not yet Kevin
Inspector says he needs approval letter from manufacturer to install isolation kit
Siemens manufacturer is not ready to give it, they say these gang meters are for service entry onlySo we are in a quandary
Expert:  Kevin replied 1 year ago.

OK, thanks for the replies.

1) Unfortunately, I don't have experience on a isolated neutral kit for a meter can. Yes, I agree that meter cans are typically rated for service entry as that is the most common installation. However, I don't see why a neutral isolation kit can't be installed in the meter can as it would isolate the neutral from the metal can enclosure similar to how a sub-panel neutral is isolated.

I am going to opt out of the question and place it back to the open board. We have a few other electricians here who may have experience on your particular application. Perhaps one of them has come across an isolated neutral at a meter can and they can better assist you.

No need to reply back to me. You will be notified once another electrical expert picks up the question...........Thanks............Kevin

Expert:  Mike G. replied 1 year ago.

Hi, I'm Mike G and I'll be glad to assist you. I saw the picture. Is there a disconnect ahead of the flex in the picture? We can never use flex on the exterior of a building and always have to Bush the connector. No matter, just exactly how this installation is layed out.

Customer: replied 1 year ago.
Hello Mike thanks for contacting me.
Attached is the diagram
We have three diaconnectors
This is placed inside the building
For 8 appartments
Expert:  Mike G. replied 1 year ago.

The first thing to do would be to contact the utility company to see what their position is on the matter. Doing anything in the meter can is up to them. I did find isolated neutral kits online by Seimans. They are at Westway Electric for around $88.00.

Customer: replied 1 year ago.
Utility company has given approval a while back after which we installed all this equipment.
Inspector would not approve isolation kit so we are stuck
Customer: replied 1 year ago.
you think if there are any design flaws
This building is grandfathered it's about 80 years old
Expert:  Mike G. replied 1 year ago.

Art 250.192 exception 2 may be the way out if the placement of the disconnect is considered adjacent to the meters, in which case they wouldn't need to have an isolated ground. From the print, that would be a stretch.