Wire sizing for emergency generator

[stevemechanical]

I need help with sizing the electrical feeder from the emergency generator to the automatic transfer switch. It is for a 50KW 208V/3PH, 0.8 pf, natural gas unit. The cut sheet says 173 amps Standby and 139 amps Prime. What amperage do i size it for?

Thanks

 

[dpc]

See NEC Article 445. Basically, at least 115% of generator nameplate current rating.

 

[davidbeach]

And it may well be that neither of those numbers are the nameplate rating.

 

[waross]

Hire an electrician. Save a smoke.

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

 

[7anoter4]

As the rated power is 50 kw the rated current will be 173.5 A [more or less as Stand-by].As dpc said [see NEC 445.13 ] the conductor has
to be suitable for 173.5*1.15=200 A.Now, it is not so simple since art.445.15 will send you to 220.61 and 250.30(A).
But in order to find the type and cross-section of the required cable you need other articles-and may be some other calculation. So waross
advice it seems to me suitable also.