Modular Meter Center Main Disconnect Switch

Status
Not open for further replies.

designer82

Senior Member
Location
Boston
When is a modular meter center required to have a main disconnect switch that shuts off power to all?

I see this done sometimes with a main disc. switch and sometimes without (just a tap box)
 
Under the 2020 code, as far as I know, there are no currently available multiple meter centers that do not need an upstream main. The meter centers on the market do not comply with 230.71(B)(4).
 
Under the 2020 code, as far as I know, there are no currently available multiple meter centers that do not need an upstream main. The meter centers on the market do not comply with 230.71(B)(4).
That doesn't seem right. I would think any of the currently available multiple meter centers could comply with 230.71(B)(4).

A Meter Center with a main lug terminal box and 6 single meter branch device sections would comply with the 2-6 service disconnecting means requirements in 230.71(B).
 
Under the 2020 code, as far as I know, there are no currently available multiple meter centers that do not need an upstream main. The meter centers on the market do not comply with 230.71(B)(4).
Designer82, the reason I asked about what code, is 230.71 B 4 had a very significant change from the 2017 version. There is much confusion in the industry and this forum about implementation. So make sure you know the difference between the 17 and 20
 
That doesn't seem right. I would think any of the currently available multiple meter centers could comply with 230.71(B)(4).

A Meter Center with a main lug terminal box and 6 single meter branch device sections would comply with the 2-6 service disconnecting means requirements in 230.71(B).
The do not comply with the separate compartment part of the new rule. When you take off a cover, the bus for the other meters is exposed and not compartmentalized as required by the code change.
There is work going on in UL 98 to change the product standards for compliance with the NEC.
 
When you take off a cover, the bus for the other meters is exposed and not compartmentalized as required by the code change.

I don't see any language like that in 230.71(B)(4). Only that each disconnecting means be in a separate compartment. They would be with Single Meter branch sections.

There is work going on in UL 98 to change the product standards for compliance with the NEC.
I would think the change in UL 98 product standards would be for multiple meter branch sections.
 
I don't see any language like that in 230.71(B)(4). Only that each disconnecting means be in a separate compartment. They would be with Single Meter branch sections.


I would think the change in UL 98 product standards would be for multiple meter branch sections.
But they are not in separate compartments...when you access the disconnect, you have access to other disconnects and line side busing.
 
I don't see any language like that in 230.71(B)(4). Only that each disconnecting means be in a separate compartment. They would be with Single Meter branch sections.


I would think the change in UL 98 product standards would be for multiple meter branch sections.
Most are like this with a single cover that accesses more than one service disconnect and that is what the 2020 code change prohibits.
1622765587933.png
 
Most are like this with a single cover that accesses more than one service disconnect and that is what the 2020 code change prohibits.
View attachment 2556759

They make those sections with a single meter/disconnect...you don't have to get a 4 meter high configuration. Get six of those sections with a single meter/disconnect and it would comply with the 2020 230.71(B)(4).
 
They make those sections with a single meter/disconnect...you don't have to get a 4 meter high configuration. Get six of those sections with a single meter/disconnect and it would comply with the 2020 230.71(B)(4).
Now I under stand what you are saying. My understanding of the term "meter center" is the type of equipment that I posted the image of. I don't see a single meter/disconnect as a meter center. Around here that would be a meter/main.
 
Now I under stand what you are saying. My understanding of the term "meter center" is the type of equipment that I posted the image of. I don't see a single meter/disconnect as a meter center. Around here that would be a meter/main.
If it had more than 6 meters, it would have a single main and of course the branch breakers wouldn't be service disconnects so there would be no issue (I would call that a meter center). A 2-6 gang meter without disconnects would of course not be an issue. The issue is a 2-6 meter center that has 2-6 service disconnects. I guess one option for the manufacturers is to just supply these with a single main (which I think is what David is saying), but as you say, I guess there is work to make them comply with the separate compartment wording.

A little aside: I don't think it's fair or consistent that panel boards got separate enclosure wording while meter centers got separate compartment wording.
 
....
A little aside: I don't think it's fair or consistent that panel boards got separate enclosure wording while meter centers got separate compartment wording.
"Compartment" is a term often used for MCCs and Switchgear, and provides separation close to that of a separate enclosure for those applications.

However that is part of the issue with UL98 as "compartment" is not really defined. One of the proposals for UL 98 would have permitted the use of insulating barriers to provide a "compartment".
 
Status
Not open for further replies.
Top