How to Trouble shoot this???

Square D sells a UL Listed interlock kit that permits the generator connection to be SAFELY backfed to the panel. It is available on E**y for about $70 + shipping.

The neutral is not disconnected from the utility, and it is not disconnected in any of the "whole house" transfer switch installations that I have seen.

You can also insert a disconnect outside there the generator connection will be make. The outdoor rated disconnects that are often used for Air Conditioner installations are quite inexpensive.

The link below will take you to the other thread on this subject.

https://terrylove.com/forums/showthread.php?t=15067

Three phase two position disconnect???????????

What about a three phase two position disconnect? Not that its code, but you can have utility power on one side, and generator power on the other. The three phase will let you disconnet even the neutral. Will get quite expensive though.

I bought a generator last Winter when we lost power for days.
It was pretty inconvenient running cords everwhere.

It's on my "to do" list to have an electritian come out and install a transfer switch on my panel.

Last year I disconnected the furnace from the house wiring, and then when the power came back on, I had to rewire it.
Yep, need a transfer switch.
That would have been so much nicer.

You don't want to break the neutral, because it is also the ground at the power entrance panel, or if you do break it you need another ground rod at the disconnect switch.

Rancher

I once got a little tingle when I grabbed my camper pop up door at a campground. Thinking that was pretty strange, and before I let my wife enter the camper I got out my meter and poked one lead into the ground and the other to the door knob. I read the full 120 volts! It turned out that the electrician upstream had reversed the hot/neutral connection after wiring in a new rental cabin. I saved the day but this is certainly not an unheard of possibility with a back up generator setup.