Emergency generator

[hhsting]

I have high rise that has diesel engine driven generator with 660 gallon subbase tank 450kw/562kva, 480/277V three phase outdoor that has 250A main breaker and 600A main breaker.

NEC 2017 section 700.12(B)(2) requires the generator to run not less than 2 hours full demand.

Questions:

1. How does one calculate if the above generator can run not less than 2 hours full demand typically?

2. Do diesel driven generator have internal combustion engine as prime mover typically or not?

 

[d0nut]

1. You look at the fuel usage at full load (in gallons per hour) and divide the capacity of your tank by that number giving you hours of runtime. Without knowing your exact generator, I would expect the subbase tank would provide 20 hours or so of runtime.
2. Yes. That is the diesel engine that is attached to the generator end.