Residential Generators Neutral

[Oakey]

Hi all...I see there is a lot of info on generators in here but I still am unclear on a few things. I am wiring a small 8,000 watt genny, it is going to feed a 100 amp auto transfer switch then to a small sub panel . It is not controlling the main house panel just a few emergency circuits in the sub. The transfer switch does not switch the neutral it is just a plain terminal bar.
My question is about the neutral configuration:
The generac genny and transfer switch both come with the neutral bonded from the factory, what would be the correct way of configuring them? I assume I need to remove the bonding jumper in the switch? Thanks

 

[templdl]

This is the way that I understand it:
The problem is that the generator's Neutral is bonded to the grounding conductor/frame of the generator and as such the neutral conductor would be bonded to the grounding conductor both at the service entrance and at the generator. Unless you grounded the generator to the residential ground rods and used a transfer switch that switches the neutral the neutral.
It would be more practical to simply remove the neutral to ground connection at the generator. As such you will be retaining the single grounding point at the service entrance and the equipment grounding conductor would be carried from the service entrance through to the frame of the generator grounding the generator. The generator manufacturer should be aware of this issue. Small generators for the most part are manufactured to be stand alone devices where the neutral is bonded to the frame.

 

[PaulWDent]

Avoiding double neutral bonding

Avoiding double neutral bonding

I had the same problem in a PV system using Xantrex inverters. The problem there is, the Xantrex inverters use the grid as a battery charger if the sun don't shine, so they have a neutral coming in that is bonded at the service entrance; but the neutral coming out is the same as the neutral coming in, so that is bonded at the service entrance. Now when I run from the inverter to the solar/utility transfer switch at the subsistence panel, if the transfer switch doesn't switch the neutral, but just parallels the inverter and utility neutral, then I have two neutral paths. I thought about switching the neutral too at the transfer switch, but this causes other problems. The solution is not obvious: The utility feeder to the inverter for its battery charging mode has to be the same as that which feeds the transfer switch: It just stops off at the inverter, then continues on to the transfer switch in a single conduit that now has one neutral and two hots, a utility hot and an inverter hot.

So this issue happens all the time with "separately derived systems" and the code will sometimes lead you astray.
Here is how you will know if you got it right: Use an electric guitar with a magnetic pick up in the house: If you got it wrong, it will hum like hell.