service entrance rated transfer switch ahead of metering?

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twils75

Member
Is it legal to place a service entrance rated transfer switch ahead of a triple stack modular meter assembly? Im looking to provide a gen service to a single premises which consists of one 200A service and two 100A services.
 

twils75

Member
thanks - If I CANT put a transfer AHEAD of the premises metering - then would there be any other way to provide backup power to three meters off one backup generator?
 

frankft2000

Senior Member
Location
Maine
Wouldn't that mean that when the generator was running, that the meters would still be turning in the power company's direction?
 

twils75

Member
great thought

great thought

Thats a good question, Frank. Not sure on this one. Im wondering how, if at all possible, to provide backup protection for a single commercial building with 3 meters (each serving a single floor); off on one single generator. Ive done quite a few resi gen setups - but this ones got me a little confused. Any help at all is greatly appreciated. thanks
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
If the poco would let you you could put a TS ahead of the 3 meters but you would also have to have 3 individual TS for each apt. after the meter. I can't see it working any other way but I haven't thought about it much.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Nevermind I don't think my setup will work either. I thought I had it but I think not- I am not sure about the control circuits and how that would work.
 

hornetd

Senior Member
Location
Maryland
Occupation
Journeyman Electrician, Retired
thanks - If I CANT put a transfer AHEAD of the premises metering - then would there be any other way to provide backup power to three meters off one backup generator?
I think you would have to put in three transfer switches so as to transfer the Service Feeders to the Generator upon loss of Utility power. The generator start contacts in each switch would need to be wired in parallel. Installing three switches will definitely raise the cost of the installation but I don't know of another way.
 

iwire

Moderator
Staff member
Location
Massachusetts
Thats a good question, Frank. Not sure on this one.

It would spin the meters.

Im wondering how, if at all possible, to provide backup protection for a single commercial building with 3 meters (each serving a single floor); off on one single generator.

You would need three transfer switches connected to the single generator. Not that usual.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
You would need three transfer switches connected to the single generator. Not that usual.
Bob that was my first thought but i started to think what happens if power goes off on one unit and not the others. That's why I thought you would need one main one ahead of the meters. When that went off then the generator would kick in and feed the wires from the other transfer switches.

Help me with the hookup if you will. Do all three units have to loose power to energize the genny?
 

iwire

Moderator
Staff member
Location
Massachusetts
Bob that was my first thought but i started to think what happens if power goes off on one unit and not the others. That's why I thought you would need one main one ahead of the meters. When that went off then the generator would kick in and feed the wires from the other transfer switches.

Help me with the hookup if you will. Do all three units have to loose power to energize the genny?

Assuming they are Automatic Transfer switches set up for two wire start you would just put all the ATS start contacts in parallel so if any one ATS lost normal power the generator would start.

If for some reason one units main blew and the other two still had power the one ATS without power would transfer and the other two would remain in the normal position.

We often install single generators that supply both standby and emergency loads, that means we must have at least two transfer switches.

We have also placed large generators that supply two buildings with transfer switches in each building.
 

Jim W in Tampa

Senior Member
Location
Tampa Florida
Would assume they are not planned to run long so spining meters might not be huge issue. Who is paying for the fuel ?
Bottom line is POCO and really don't see them allowing you to be on there side of meters for anything.
 

ceb58

Senior Member
Location
Raeford, NC
Assuming they are Automatic Transfer switches set up for two wire start you would just put all the ATS start contacts in parallel so if any one ATS lost normal power the generator would start.

If for some reason one units main blew and the other two still had power the one ATS without power would transfer and the other two would remain in the normal position.

We often install single generators that supply both standby and emergency loads, that means we must have at least two transfer switches.

We have also placed large generators that supply two buildings with transfer switches in each building.

The only down side to the whole set up is if tenant #2 didn't pay the power bill and poco came and booted the meter then the gen will run and transfer to tenant #2. But there is no other way around it.
 

Smart $

Esteemed Member
Location
Ohio
The only down side to the whole set up is if tenant #2 didn't pay the power bill and poco came and booted the meter then the gen will run and transfer to tenant #2. But there is no other way around it.
Short of a more elaborate setup, perhaps putting the "run" contacts in series is better.

Are we talking just a triple meter stack... or a combo stack with disconnecting means?
 
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