Cable sizing for generator fed loads

[Designer69]

When sizing feeder cables for stand-by generator fed loads, would you size the cables per connected / demand total load or the max output the generator can handle?

thank you!

 

[qcroanoke]

When sizing feeder cables for stand-by generator fed loads, would you size the cables per connected / demand total load or the max output the generator can handle?

thank you!

Size to the generator output breaker

 

[Julius Right]

NEC article 445.13 Ampacity of Conductors.
?The ampacity of the conductors from the generator terminals to the first distribution device(s) containing overcurrent protection shall not be less than 115 percent of the nameplate current rating of the generator?. But also:
?Conductors that must carry ground-fault currents shall not be smaller than required by 250.30(A).?

 

[Smart $]

NEC article 445.13 Ampacity of Conductors.
?The ampacity of the conductors from the generator terminals to the first distribution device(s) containing overcurrent protection shall not be less than 115 percent of the nameplate current rating of the generator?.

In many cases, the first OCPD is integral with the generator.

 

[TimWA]

Size to the generator output breaker

Onboard generator breaker is sized by the manufacturers UL listing, it is to protect the generator only. The panel breaker and feeder conductors can be sized 115% to the generator nameplate output rating, disregard onboard breaker.

 

[qcroanoke]

Onboard generator breaker is sized by the manufacturers UL listing, it is to protect the generator only. The panel breaker and feeder conductors can be sized 115% to the generator nameplate output rating, disregard onboard breaker.

They can be but they do not have to be.