comercial load

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normbac

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I was asked to install a 100 amp run for a power supply from a 480v 250a panel, there are already three other 100 amp runs supplying the same type of power supply and a 100 amp breaker to a 120-280 transformer for a lighting panel.
They use these power supplies maybe 2 at a time but the potential to use all at the same time is there, would this install be a violation due to the potential load? There is a 600amp switch gear next to the panel should I tell them another 250a 480v panel install is required off the 600a ?? Any input is appreciated, I am somewhat new to commercial installs & calculating panel loads TIA
 
they are power supplies so they pull average 50 amps but they sometimes run them up at their capacity which is 100amps
 
normbac said:
they are power supplies so they pull average 50 amps but they sometimes run them up at their capacity which is 100amps
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Even with full capacity I think they wont even pull one hundred amps.
I think you should be OK to install. :smile:
Are they continuous or noncontinuous loads?
 
jmsbrush said:
Even with full capacity I think they wont even pull one hundred amps.
I think you should be OK to install. :smile:
Are they continuous or noncontinuous loads?
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they are non continuous but Not understanding how it would be less than 100 total if they are capable of 100 amp loads per supply and there are four how maybe I am not explaining clearly
 
jmsbrush said:
Even with full capacity I think they wont even pull one hundred amps. I think you should be OK to install. :smile:
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Assumptions usually lead to the mother of all screwups.

I would let the customer make the decision with the recommendation to add another panel. Two power supplies pulling 200 amps total plus the other loads is very close to full capacity, not worth the risk IMO.
 
Cow said:
Assumptions usually lead to the mother of all screwups.

I would let the customer make the decision with the recommendation to add another panel. Two power supplies pulling 200 amps total plus the other loads is very close to full capacity, not worth the risk IMO.
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Yeah I think if they dont want the additional panel I am better off passing on this one I wasnt sure if calculations were different when using 480 but I guess a load is a load and should not be exceeded in any application
 
The only way to answer the question is by knowing the actual load current of the equipment. It would be darn right odd for a piece of equipment on a 100 amp breaker to draw 100 amps.

What does the machine label actually say?
 
iwire said:
The only way to answer the question is by knowing the actual load current of the equipment. It would be darn right odd for a piece of equipment on a 100 amp breaker to draw 100 amps.

What does the machine label actually say?
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The supply is A/C to D/C the modules inside say 3.1 kw @ 277 there are ten total
Is this correct
277x1.732 = 479.764 so 31kw divided by 479.64 = 64.63 amps ?
 
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