20 kw 25 kva Cummings generator.

[Kg808]

Hey all!
doing a bid for installing a Cummings single phase 120/240V 20KW back up generator. It’s model number C20 N6

i cannot, for the life of me, find out what size the circuit breaker is for the output on the generator. I can do the obvious division and see what the max output is in relation to its 20kw rating but I would really like to make sure I spec out the right wire size for the OCPD and Load. But there is no place I can find that will tell me what the ratings of this thing are.
I don’t do much work with these generators and I’m hoping someone out there has installed one and can tell me.. or there is a generator guru out there that can confirm my simple math and I’ll just run #2’s and call it a day.

Fyi i even called cummings direct and they responded like a deer in the headlights. They kept telling me that the battery charger needed a 120v circuit...? I eventually hung up.

Thanks!

 

[JFletcher]

A 20 kilowatt generator with a 240 volt output would probably have an 80 or 90 amp breaker with number 3 or 4 copper wire. That said, I seem to recall that some Generac generators, perhaps in the 22 kilowatt range, have one hundred amp breakers and number 2 or number 3 wire.

Eta : check the size of the lugs on the generator, some of the ones I have worked on do not have lugs that will accept the maximum size aluminum wire that should be run to them, especially if you are up sizing for voltage drop.

 

[MTW]

I think you need to do a little more studying up on the install requirements, rather than just the output wire size. Most models require a automatic transfer switch as well.

The exact model number determines the breaker size as ordered, comes in 1 or 3Φ, single or dual breakers and 80 or 100% rated. You need to check with the dealer on the exact model provided.

Installation manual

https://www.norwall.com/product_pdfs/9737_rx_powerconnect_installmanual.pdf

Operator manual

https://www.norwall.com/product_pdfs/4245_rx_powerconnect_operatormanual2.pdf

Data Sheet
https://www.google.com/url?sa=t&rct...-5693-EN.pdf&usg=AOvVaw116wZwgR_NMHW1eUsPge2X

MTW