Lighting Control Panels / Relays AIC ratings

[necnotevenclose]

I'm feeding a 277V/1PH lighting control panel from a 480Y/277V panel that has an available fault of 16k Isc. The lighting control panel has a rating of 14k AIC at 277V.

Would the available fault current for a single phase load be less than a 3-phase load?

 

[dpc]

A 277 V single-phase panel? That's a new one.

Fault current will be reduced by the feeder impedance from the main 480 V panel to your sub-panel.

But you can't make assumptions - you need to calculate.

There could also be a series rating between the breaker in the main panel and the sub-panel breakers.

David Castor

http://www.cvoes.com

 

[jghrist]

Further to what David said - the fault will be single phase, so you need to calculate Ø-grd faults.

 

[waross]

Is this really a single phase panel or are you using two phases of the three phase supply?

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[jraef]

If you have ONE hot wire and ONE neutral wire going to the LCP from the 480/277V panel, then you need to determine the Isc at 277V {phase to neutral), not 480V. But if you have TWO hot wires and a neutral, then you have to use the 480V value.



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