Transformer between service XFMR and customer meters

[tecorp]

Hello,

I am working on a project for a multi story multi family building. There are meter stacks for each individual unit. So current single line shows 208/120V service that is distributed to each meter, which then goes to each load center per unit. The proposed service voltage comes with a ton of voltage drop issues.

I want to propose that we go to a 480/277V service so that these voltage drop issues are solved. However, I am unsure if this will be allowed by SCE since the new single line will become 480/277V service, then a step down transformer (I am guessing this is SCE owned), which is distributed to each meter, which then goes to each load center per unit.

Again, the service is SoCal Edison.

Just wondering if anyone had any input on this. I am looking at SCE's ESR and am not finding anything concrete.

Thanks,
te

 

[don_resqcapt19]

I would expect the 480 to 208 transformer would be customer owned and on the load side of the service point.

 

[tecorp]

I would expect the 480 to 208 transformer would be customer owned and on the load side of the service point.

So would you see any issue with this SLD?

Incoming 480/277V (utility owned) ->
Step down transformer (customer owned) ->
Meter stack for each individual unit (not sure who owns this, but I'm sure the owner will not want to deal with the utility. They will want SCE to bill and get payment from each apartment lessee)

 

[tortuga]

So would you see any issue with this SLD?

Incoming 480/277V (utility owned) ->
Step down transformer (customer owned) ->
Meter stack for each individual unit (not sure who owns this, but I'm sure the owner will not want to deal with the utility. They will want SCE to bill and get payment from each apartment lessee)

You can do a 480V service -> 480V CT meter -> 480V service disconnect -> customer MDP -> feeders -> customer owned transformers -> customer owned sub meters.
And if your doing that its better to bring the 480V feeder up the floors and do single phase 120/240 transformers for a floor or group of floors.

 

[jim dungar]

The proposed service voltage comes with a ton of voltage drop issues.

How does changing the service voltage to 480V change the voltage drop issue when your distribution, to each unit is 208Y/120?

The power company will only provide you one voltage. Your client would be responsible for the losses and voltage drop across the 480:208Y/120V transformer. And don't forget the issue of providing the metering for each unit.

 

[tecorp]

How does changing the service voltage to 480V change the voltage drop issue when your distribution, to each unit is 208Y/120?

The power company will only provide you one voltage. Your client would be responsible for the losses and voltage drop across the 480:208Y/120V transformer. And don't forget the issue of providing the metering for each unit.

we'd be distributing 480v across campus up to a step down xfmr right next to the individual meters instead of distributing 208v across campus to the individual meters

 

[don_resqcapt19]

we'd be distributing 480v across campus up to a step down xfmr right next to the individual meters instead of distributing 208v across campus to the individual meters

I think you need 208 volt services at each of the campus locations where there will be meters.

 

[Hv&Lv]

we'd be distributing 480v across campus up to a step down xfmr right next to the individual meters instead of distributing 208v across campus to the individual meters

You want to install a customer owned transformer on the Line side of the meter?? That's not gonna fly.

 

[electrofelon]

When you start getting into transformer capital cost and losses, some more runs of aluminum conductors for voltage drop start to look pretty good

 

[Knightryder12]

Will the utility not put multiple transformers on the campus to reduce your service lateral lengths to help with the VD issues?

 

[MyCleveland]

we'd be distributing 480v across campus up to a step down xfmr right next to the individual meters instead of distributing 208v across campus to the individual meters

Either the utility is going to set multiple transformers or you are. Involved with numerous multi-building apartments on a single site and all were provided with a MV loop / path around the site for the utility to install MV wiring. It was always direct buried with ducts installed underground to allow each utility to cross under site roadways. All of this was coordinated in advance with the designated utility engineer/designer.

A few times we were able to serve two buildings from a single tranny. Dependent on size of buildings / apartment counts per building the voltage varied from 120/240-1P-3W and 120/208-3P-4W. A few rural utility co-ops in TN would NOT allow 3P for the buildings even though they were 4-story / 80+ suite buildings. They wanted to charge a commercial rate for the residences. In this case, they did provide two voltages, 120/240 for the apartments and 3P for the house loads. Still too large to serve with a single 120/240 tranny, they installed one at each end of the building. Distribution to each apartment resulted in some large aluminum feeders to compensate for the distances...VD.

Every developer discussed the idea of owning the metering and site distribution equipment and taking power at the utility MV primary. In the end, NONE opted to go this path.

Have you had a meeting with the utility to discuss options?