Our power goes off on a frequent basis. If it is off more than 8 hr I need to power up with my own generator 8kw, to prevent spoilage and to run the well. My question is do you have to disconnect the neutral also and run the neutral to the generator or can the neutral be common to both power sources? Also if a transfer switch is installed does it have to have a switching leg for the neutrals? Also if the neutrals do need to be switched can we use a three phase box to accomplish switching the neutral and both power legs for the generator. Thanks JG

Answer:

Maybe.

The generator should contain a strap from it's neutral to ground of the output connector that can be removed. When that generator is operate din stand-alone mode the strap should be placed back. i.e. not connected to the house.

1. Strap removed: No need to switch neutral
2. Strap exists and generator has it's own ground rod. Neutral should be switched.

Case 1:
Ground/reference of system supplied though existing panel.

Case 2:
Two ground rods in parallel when transfer swich off - Good thing. Lowers ground resistance.
Here you don't want two neutrals connected to the same place.

Case 3: Grounds and neutrals both connected always (Not allowed)
You don't want two references.

#1 likely for portable generators
#2 likely for stand alone generators