Generator install - unique home wiring or not

Ok, so as a follow up - the licensed genny guy came in and did his stuff. He followed the rules related to the multi branch circuits, etc.

I was doing some testing to make sure all the label are correct and I am having a MINOR issue (I THINK).

I had a multi branch circuit that controlled the furnace fan (furnace is gas) and the living room lights. So he moved both circuits over to the genny panel (each on its own breaker) and tied the shared neutral together. All seems on the up and up....

However...now for the life of me, I can't get the living room lights to shut off (via the breaker). I turn the new genny breaker off for the furnace and that works fine. Then I turn off the circuit for the living room and heck the lights are still one.

Now it gets weird....so I decide to make sure the hot is indeed turning off with the breaker, and it is. YET SOMEHOW the lights are staying on.

I assume I have a PROBLEM somehow with the neutral back feeding, but even if I turn off BOTH CIRCUITS (furnace and living room) I still get the lights to stay on...yet furnace is out. ?? Is there a way to test for this safely? Any other clues ?

Or is everyone as lost as me

With that breaker turned off turn off all the breakers one by one. If the light goes off, turn the first one back on if the light comes back on you have a connection somewhere that should not be connected.

Call him back and ask him what he did. It could be an honest mistake that needs a quick fix.

I'd go with Neal's approach before calling (unless he'll come out for free), I wouldn't be surprised if it's a house issue, I found an instance where loose THHN had been spliced together in the basement of a friends house once. What was that thing called that they used in Europe back in the day to have 30A circuits, ring wiring... where you used the wire as the ballast resistor to dissipate any difference between the two hot wires (because there's always some phase difference)... Ha, look at this and you'll feel better about the wiring in your house. http://en.wikipedia.org/wiki/Ring_circuit