Calculating Service Size for Apartment Building

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bratzpack

Member
Location
NY
Is a 300A service enough to supply power for 10 apartment units and 400A service for 14 apartment units. Each apartment unit will have electric cooking rated at 9.1kw each. Service voltage is 120/208V, 3Ph, 4 wire.

I sized the main ocpd for the panels at each apartment between 100A to 150A @ 120/208V, 1 Phase.

I need a more experienced eye to look at my calculation and confirm that it is adequate. I attached my calculation for your comments/corrections. Please advise if I missed a step/procedure that might have affected the demand load result. Thank you in advance for your help.
 

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Last edited:

david luchini

Moderator
Staff member
Location
Connecticut
Occupation
Engineer
Your comments, corrections and opinions are highly appreciated. Please post your reply. Thank you.

Your range demands in Step 5 of the building 1&2 service sheet are larger than they need to be. For 8 units its 23kW (not 25) and for 10 units its 25kw (not 29.)

You could also have use the optional method in 220.84. It makes the demand a bit lower for each of your buildings.

There's no laundry equipment?
 

Smart $

Esteemed Member
Location
Ohio
Your range demands in Step 5 of the building 1&2 service sheet are larger than they need to be. For 8 units its 23kW (not 25) and for 10 units its 25kw (not 29.)

You could also have use the optional method in 220.84. It makes the demand a bit lower for each of your buildings.

There's no laundry equipment?
Hard to tell what is actually there (or going to be). His building sheets indicate 10 and 14 unit buildings, but only 7 and 5 apartments respectively, with some multi-unit apartments. Are the apartments comprised of more than one "unit" going to have one range per "unit" or one range per apartment???
 

bratzpack

Member
Location
NY
Your range demands in Step 5 of the building 1&2 service sheet are larger than they need to be. For 8 units its 23kW (not 25) and for 10 units its 25kw (not 29.)

You could also have use the optional method in 220.84. It makes the demand a bit lower for each of your buildings.

There's no laundry equipment?

Thank you for your comment, I will do the necessary correction as noted. There will be a common laundry room to be located in a separate building, the space heating & hot water for each apartment building will come from a boiler system also located in the separate building.
 

bratzpack

Member
Location
NY
Hard to tell what is actually there (or going to be). His building sheets indicate 10 and 14 unit buildings, but only 7 and 5 apartments respectively, with some multi-unit apartments. Are the apartments comprised of more than one "unit" going to have one range per "unit" or one range per apartment???

Building #1 has 10 apartments and Building #2 has 14 apartments. Each apartment will have one electric range.

For example, in Building #1 there is;
one (1) Apt. Type 1A
one (1) Apt. Type 1B
one (1) Apt. Type 1C
two (2) Apt. Type 1D
two (2) Apt. Type 1E
two (2) Apt. Type 1F
one (1) Apt. Type 1G

So, for Building #1, there is a total of 10 apartment units.
 
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