Series rating HVAC loads

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kjrise

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I have a 600amp 208v distribution main lug only panel fed by main panel with a 600amp 100% rated breaker @ 65kaic rating.
The HVAC distribution breakers in this panel are rated at 18kaic or series rated at 65kaic. Can I series rate this panel?
The motor loads are at about 225amps. Does the 100% rated feeder breaker effect the need to fully rate this panel?

Thanks
 
Re: Series rating HVAC loads

The driving factor is not the AIC rating of the breaker, but the available fault current. You must determine the fault current at the HVAC breaker location to determine their AIC requirement. If it turns out to be more than 18ka, you may use series rating if they are listed by a manufacturer as series rated above the available fault current. If they are not listed as series rated, you are out of luck.
Jim T
 
Re: Series rating HVAC loads

You must confirm any possible series rating with the circuit breaker manufacturer.

Most series ratings are not applicable if there is a large amount of motors involved that can feed current back into a fault.
 
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