generator grounding

[charlie tuna]

i had a call from another electrician and he explained that he had a problem with the two pole 30 amp output breaker tripping when the generator 's ground wire was connected to the ground terminal of the panel it was set up to supply. i have my generator's frame grounded to the panel that it supply's and i have never had a problem. anyone run into this??

 

[steve66]

Some of the cheaper generators are not suitable for connecting to a premisis wiring system. For example, I think the ground of some portable generators is tied to one of the hot wires. Instead of having each hot being 120V to ground, one is 120V and the other is 240 volts. So there would actually be 120V between the neutral and the ground. If you connect this to a panel that has a N-G bond, the breaker would trip.

Steve

 

[ramdiesel3500]

Another possibility: Does it have GFCI protection on the 30A breaker? If so, then connecting the ground to the grounding system of a panel that is bonded will create a parallel path for neutral current causing the GFCI to trip! In this case, you would need to disconnect the bond between the neutral and ground at the generator. Only problem with this is that when you use the generator for a different purpose, you would have to remember to re-connect the bond again!

 

[hockeyoligist2]

I agree with ramdiesel on that one, I've ran in to the same problem, several times.