Multifamily dwelling

keith gigabyte

Senior Member
Somewhat new to load calculations. I have a commercial building being converted into apartments. it is 2 levels. the 1st level is a total of 4,675 sq ft. 2nd level is 2,000 sq foot warehouse only space. Apartments range in size from 1055 sq foot to 640 sq foot.

The 1st floor will be 4 newly framed apartments and 1 existing office space. the 2nd floor will be all warehouse storage. each apartment will have the following. 5000 va range, 4500va hot water tank, microwave, 5000 va clothes dryer, 7200 va Air conditioning compressor and 800 va air handler motor.
doing the calcs in annex deration due to 4 units. I come up with 133 amps to 137 amps depending on sq footage. If someone could check me on that I would appreciate.
House load would be approximately 360 sq foot of hallway lighting and 1 fire alarm panel. existing 900 sq ft office is fed with 100 amp panel and load calc comes out at about 50 amps..900 sq ft no appliances only 4500 h2o tank 8000 va A/C
2nd floor warehouse at 2000 sq ft is 10 amps no ac no h20 tank.

My grand total 240 single phase amperage for building comes out at 584 amps. sizing at 125% the service should be rated at 730 amps. Am I allowed to reduce the demand factor since there are 6 occupancies? 4 apartments, 1 office, 1 warehouse?

I plan to feed this with a 10 bank meter stack with main breaker. currently i have a quote from distributor for meter center with 600 amp breaker and buss rated at 600 amp. Each apartment would have 150 amp main at meter, house would have 100, office would have 100, and 2nd floor would have 100. all at meters My main concern is the 600 amp rating of main and buss being heavy enough.

Thanks for any help