Utility Demand Imbalance

[xguard]

I have a building with 272 kw peak demand according to the utility company. Does anyone know if they measure the demand using the highest leg or if it's a summing situation. If the phases aren't evenly loaded, and their demand value doesn't take this into account could I have higher current on one leg than the calculation below shows?

208/120 3 phase. Assuming 0.9 pf (that's what I've seen at other buildings not sure that's accurate for this building.)
272kw/0.9pf = 302 kva.
839 amps
839 amps x 1.25 = 1049 amps

My concern is I'm planning to reduce the over-current protection to 1200 amps (1200 amp fusible switch ahead of switchboard). (Acknowledging the 1.25 is applied to the entire load gives me some cushion.) The building currently has a 1600 amp switchboard with a 1600 amp fixed circuit breaker (1967).

 

[texie]

The POCO demand meter is looking at total power and does not take into account imbalance. Also note that even in a balanced circuit the current could at times be much higher than the demand readings would indicate.

 

[electrofelon]

I have a building with 272 kw peak demand according to the utility company. Does anyone know if they measure the demand using the highest leg or if it's a summing situation. If the phases aren't evenly loaded, and their demand value doesn't take this into account could I have higher current on one leg than the calculation below shows?

208/120 3 phase. Assuming 0.9 pf (that's what I've seen at other buildings not sure that's accurate for this building.)
272kw/0.9pf = 302 kva.
839 amps
839 amps x 1.25 = 1049 amps

My concern is I'm planning to reduce the over-current protection to 1200 amps (1200 amp fusible switch ahead of switchboard). (Acknowledging the 1.25 is applied to the entire load gives me some cushion.) The building currently has a 1600 amp switchboard with a 1600 amp fixed circuit breaker (1967).

I have done similar where I have upgraded an old service but decreased the size due to having utility demand data. Personally I would have no problem going with 1200 amps but I am not familiar with the facility and the likelihood of increased load or what the owner does or doesn't want to pay for....