Grounding requirements for standby generator

Question

I'm installing a standby generator for my son's new home build and have questions about grounding, bonding the genset.

We are installing a Kohler RXT 200 amp transfer switch between the meter base and the main panel servicing the home. The generator is Kohler 14RESAL genset. I've asked a question about this subject one other time and comments were made about the relative wisdom of switching the entire house to the generator. That's water under the bridge at this point, so lets focus on the grounding question I have.

My question regards bonding the neutral to the ground at the getset. There is a label saying the ground and neutral are bonded and there is a jumper on the connections factory installed. The transfer switch doesn't switch the grounded neutral conductor, so from what I understand, the generator isn't a "separately derived system"...so no GECs needed at the generator.

I planned on running 2 hots a neutral and a ground to the genset, but now I'm unsure. My instincts say disconnect the bonding jumper and connect the neutral to L0 (unfortunately labeled), the hots to L1 and L2 and the ground to GRND. See pictures.

Comments?

Answer 1

That is correct

You are correct that the bonding means in the generator should be pulled in this case since your transfer switch has a solid neutral; in this case, since you have a service entrance transfer switch, your bonding means will be in the transfer switch, with the "main panel" wired as a subpanel from the transfer switch.

You are also correct that a grounding electrode conductor does not need to be run to the generator location; the equipment grounding conductor from the transfer switch to the generator is sufficient to bond the generator to the grounding electrode system. (There's no requirement for local ground rods at the generator, by the way: NEC 250.32(A) says "building(s) or structure(s) supplied by feeder(s) or branch circuit(s)" need a grounding electrode system of their own, but your generator's not supplied by anything.)