In my research on generator interlocks, I see references to needing to switch the neutral to avoid backfeeding through it. None of the commercial units seem to do it. It seems to me like there would have to be more than one major problem before my little 6250 watt generator could ever impose a voltage on the neutral running out to the pole. Here is one reference, http://www.craftkb.com/Uwe/Forum.asp...eb2fdcb3a6auwe

The neutral should be grounded at your service and at the utility transformer/pole. The neutral is not switched when using an interlock device.

There should not ne anu fear of backfeeding voltage on the neutral because it is, or should be grounded.

Do not ground the neutral at the generator, however, read the manufactuers manual, the generator may need the frame grounded.

Grounding and neutrals can be confusing, and must be done correctly for safety, let me know if you are not sure of what I explained.