GENERATOR OVERCURRENT PROTECTION

[don_resqcapt19]

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But anyway, I still believe that a generator can produce enough over current to damage conductors if not protected for long term overloads and with the new specs and smaller breakers I would think it would be harder, but in the OP case with the 500 amp breaker on the generator it would be much easier, as a matter of fact I looked up the latest specs on a Generac 100kw which now shows a 450 amp breaker for the 120/240 single phase model, looking at the lock rotor rating which is the available fault current @ 35% voltage dip, show the available output is 200kva which is 833.33 amps, more then enough to damage the 600's?

I would be really surprised if the prime mover could support that amount of current for any length of time without stalling or shutting down on high temp. Looking at one 450 amp breaker trip curve, it looks like the clearing time for ~800 amp fault would be over two minutes...would the generator run that long?

 

[templdl]

Thanks for the reply. I'm going to have to take a look at the breaker tc curve and compare it to what current the generator is capable of putting out.
I'm not sure what breakers Generic may be using as they may not have the same trip characteristics as the common UL489 breakers that are used to protect wire. I know the Westinghouse/Cutler Hammer had a line of breakers that were designed to be used with generators.