optional stand-by generators, grounding ?

[bark]

Two Generators, one with service rated transfer switch, one without service rated. Only a 3 pole transfer, neutral is not switched. Does a equipment ground need to be pulled from the generator to the transfer switch? One is installed after the CT's, the one that is service rated, the other is installed after a 500 amp breaker in the main distribution panel. Is this a floating neutral at the transfer switch? Do both need ground rods at the generator.

3 different inspectors, 3 different ways to do these. Now on my fourth.

 

[Robert Hutcherson]

It sounds like the generator system is non-seperately derived system as the neutral is not switched. The neutral is isolated at the generator. You will need to install an equipment grounding conductor based on NEC 250.122. The EGC will run to the location where the equipment grounds at the service entrance equipment terminate. Read NEC 250.130(A).

Concerning the ground rods, on our installs, it seems the manufacturers documents on the generator seem to call out driving one rod. I felt it was for dispersal of lightning mainly.

Hope this helps.

 

[RUWired]

Is this a floating neutral at the transfer switch?
.

If the service rated transfer switch has the service main built in with it, the neutral gets bonded. If the service rated transfer switch is after the service main, it would float. In the transfer switch with the feeder, it would float.

Rick

 

[bark]

Thank you,

bark