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Joined: Jul 2012
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Hello,

I wanted to inquire if it is possible to estimate available electrical capacity in an electrical distribution system based on only peak demand information available. For e.g. if an 800A, 347/600V, 3-phase electrical service has a peak demand of 175kW, would it be safe to assume the following calculation to estimate available electrical capacity at unity power factor:

800A x 0.8 = 640A (max. loading)
175kW = 600V x A x 1.732 i.e. A = 168A
Available capacity would be 640A - 168A = 472A.

Would the estimation of available capacity change if there are 600V - 208V step-down transformers downstream of the electrical distribution system?

Thank you.

Joined: Apr 2002
Posts: 7,333
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You will have to calc the existing loads on each of the transformers.


John
Joined: Mar 2006
Posts: 82
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The code now allows this. You have to provide at least 12 months of peak demand data from the utility bills.


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