Generator Bonding

[kriverswaters]

We are planning on installing an 80 KW, (125 Amp), 480\277 Volt, 3 Phase, Emergency Generator and a 150 Amp, 480 Volt, Three Pole, ATS (Automatic Transfer Switch) to feed a 480 Volt, 12 circuit Emergency Panel. My questions is this: Should the Neutral and Ground be bonded together at the Generator source, or should it be isolated? They are isolated at the transfer switch of coarse. This is a non-service entrance rated application.

 

[ActionDave]

The neutral and equipment ground should not be bonded at the generator when the neutral is not switched.

When the transfer switch is after the service disconnect I think of it and the generator as sub-panels. Each get five wires, neutrals isolated from equipment grounds, each on their corresponding buss or lug.

 

[shortcircuit2]

How does an 80kw generator only have 125 amps?

 

[masterinbama]

How does an 80kw generator only have 125 amps?

It's three phase.

 

[kriverswaters]

The neutral and equipment ground should not be bonded at the generator when the neutral is not switched.

When the transfer switch is after the service disconnect I think of it and the generator as sub-panels. Each get five wires, neutrals isolated from equipment grounds, each on their corresponding buss or lug.

That is what I thought. It is just that the Generator comes from the factory with the Neutral and ground bonded together. I will isolate them. Thank You.