Peak demand exceeding panel rating

[WA_Sparky]

I'm working on a coffee shop that has a 200A 208y/120v 3 phase panel. 12 mo peak demand from utility is 83kw. Typically I default to .9 power factor. Even with that, my peak demand is over panel amperage.

Is .9 a good power factor to default to?
Is it more likely the power factor is closer to .8?
Peak demand values are peak load for minimum of 15 minutes. I'd imagine if it was 208A draw for 15 min the breaker should have tripped unless it's a faulty breaker.

 

[winnie]

I can't comment authoritatively about expected power factor in a coffee shop. I'd expect lots of resistive heating....

On the breaker, take a look at normal trip curves. A perfectly functional breaker could reasonably take 15 minutes to trip at 50% overcurrent.

IMHO the fact that demand exceeds rating probably means a problem unless this was a one off fluke such as everything coming on at the same time after a power outage.

Jon

 

[ptonsparky]

I would think if the POCO is looking at peak demand they can tell you what the PF is as well.

 

[texie]

Assuming a .9 PF, which seems reasonable for an occupancy like this, the amps would be about 255. At .8 PF the current would be even higher.

 

[WA_Sparky]

Assuming a .9 PF, which seems reasonable for an occupancy like this, the amps would be about 255. At .8 PF the current would be even higher.

Yes correct I had my PF on the wrong side of the equation, which is even worse than I thought.

From a code standpoint even if there is a reduction in load during renovation and estimated demand is above panel/feeder amperage it would require an upgraded service?