Ground wire from meter to dwelling unit tenant panel

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Volt-Amps

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I'm reviewing a drawing where there is a main service disconnect for the building, the main disconnect is connected to a meter section with 5 meters, one for house panel and 4 are for dwelling units above. I noticed that they are showing 3 conductors from each meter to the tenant panel, no mention of ground. I know EMT can be used as equipment ground if certain requirements are met, but I'm confused if ground wire is required from the meter to the tenant panel. Can someone help clarify please?
 
You are saying "from each meter" but I think you mean from each service disconnect at each meter. And, yes the EMT could serve as the EG for the feeder to each tenant.
 
Thanks Texie. There is only one service disconnect 400A the service conductors are terminated at, then comes a meter bank with no main on any of the 5 meters, then meters are connected to the respective tenant panels. So the 400A is the service disconnect, after that, meter and tenant panels would require equipment grounds, not service grounds, correct?

Power riser.jpg


I started adding my markups, but stopped at the grounding part to verify ... see below

Power riser with markups.jpg
 
Before talking any further on the grounding and bonding, you need to change this design. It is not compliant as drawn. You need an OCPD on the load side of each meter sized appropriately for each tenant. The 400 amp main could stay but it is not required. If it stays VS not having it the grounding and bonding will be different.
 
I noted to add meter disconnect at each meter (note not shown because I don't want to keep adding images of additional markups). however, if they keep the 400A service disconnect, then the meter disconnects, once added, are no longer considered service disconnects, correct?
I did mention that the 400A is not required assuming they add service disconnect at each meter, however, assuming they keep it, I'm not sure where on this diagram can the EMT be used as ground. see feeders between each meter and the tenant panel.
 
Volt-Amps said:
Thanks Texie. There is only one service disconnect 400A the service conductors are terminated at, then comes a meter bank with no main on any of the 5 meters, then meters are connected to the respective tenant panels. So the 400A is the service disconnect, after that, meter and tenant panels would require equipment grounds, not service grounds, correct?

View attachment 2562950


I started adding my markups, but stopped at the grounding part to verify ... see below

View attachment 2562952
Click to expand...
Why add meter disconnecting means for each meter?
I didn't think that was a requirement.
 
It's a Chicago project, section 560.24 states that "where a current supply is separately metered as in an apartment building, each such separately metered load shall be equipped with a meter disconnecting means which will disconnect the separately meter load from its source of supply."

I'm not sure if this is not applicable if there is a 400A service disconnect for all meters, but if I follow the code language, we need one at each meter. What do you think?
 
Volt-Amps said:
I'm not sure if this is not applicable if there is a 400A service disconnect for all meters, but if I follow the code language, we need one at each meter. What do you think?
Click to expand...
Sounds like each meter needs its own disconnecting means.
 
Volt-Amps said:
Thank all you for your help. I will ask for a separate service disconnect at each meter and delete the 400A disconnect as it's not needed.
Click to expand...
Sounds good. You'll also need a load calculation to determine whether or not the 350's are sized correctly.
 
Each meter needs not merely a disconnecting means but an OCPD. (Unless all the feeders to the unit qualify under the tap rules which is very doubtful.)
 
texie said:
..you need to change this design. It is not compliant as drawn. You need an OCPD on the load side of each meter sized appropriately for each tenant.
Click to expand...
If draft shows an existing service, seems 240.21(B)(5) tap rule may allow outside feeders to main breaker panels sharing same wall with service equipment.

That section does not require individual meter disconnects, and leaves room for future expansion with more than 5 meters / disconnects.
 
And change the 1” EMT with 1/0 thwn to 1” Sch 80 pvc with 1/0 GEC to cold water line. A GEC in metallic raceway requires bonding bushings at each end
 
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