220.84 Multifamily Dwelling demand factor if it is for services in same facility?

Cartoon1

Senior Member
Location
Florida
Occupation
Electrical Engineer
Hello all, i have a little confusion regarding 220.84 Multifamily Dwelling demand factor. I have a condomium building that has 30units. This building will require at least 2 meter center services to feed. My question is in regards to the demand factor %factor. Since each meter center is going to take care of 15 units. Do each meter center gets calculated seperate.

So for example:
Meter Center 1: 15 units - 40% Demand factor
Meter Center 2: 15 units - 40% Demand factor

OR

Meter center 1 + 2: 30 units - 33% Demand factor.

As you see the demand and sizing of meter centers will come out to be a different based on which route you take. Which is the correct way to do it?

Thank you
 

Cartoon1

Senior Member
Location
Florida
Occupation
Electrical Engineer
supply to each meter center would be based on demand factors for 15 units.

if there is any kind of common supply to both meter centers that could be sized per demand factors for 30 units.

Yes, both meter centers will be fed by the same transformer.
 

kwired

Electron manager
Location
NE Nebraska
Yes, both meter centers will be fed by the same transformer.
so total load of both can be based on demand factor for 30 units this allows you to size transformer (though if POCO transformer they will determine that) as well as any common conductors to the two meter centers.

If POCO is sizing the transformer and if each meter center is separately fed then those conductors can only use demand factors for 15 units
 

Cartoon1

Senior Member
Location
Florida
Occupation
Electrical Engineer
so total load of both can be based on demand factor for 30 units this allows you to size transformer (though if POCO transformer they will determine that) as well as any common conductors to the two meter centers.

If POCO is sizing the transformer and if each meter center is separately fed then those conductors can only use demand factors for 15 units
Typically here. The poco requires us to do load calculations (they don't say which way). Then they take that and provide a transformer based on their standards. What i do know is that poco has already said that this building will get 1 transformer only. So it seems like i can use the 30 units demand factor and there will be separate sets to each meter center going to the same poco transformer.
 
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