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Utility Fault Values
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Author:  rshummel [ Sat Dec 10, 2022 7:12 am ]
Post subject:  Utility Fault Values

I have a local utility that gave me maximum and minimum fault current values which is rare but nice. The problem is the maximum on 12,470 is around 5000 amps and the minimum is only 177 amps. The minimum values give terrible arc flash ratings for the equipment in the plant I am working in. Does this value seem right? I would think they have more than that value on the feeder in any given day under normal operating conditions. Thanks

Author:  wbd [ Thu Dec 15, 2022 9:20 am ]
Post subject:  Re: Utility Fault Values

That minimum fault value seems impossibly low as if you think about it, it is probably lower than the circuit loading. I wonder if they left a zero off and it should be 1770. I would go back and ask them to reconfirm and if you know the full load of the plant, you can convert that to the value at 12.47 and see how close it is to their lowest fault current value.

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