I hadn't thought of that part, as I forgot how your "manual transfer switch" works.
Even though I have a copy of the [I]2008 National Electric Code[/I], I'm not sure if you can - within the code - hook up a sampling circuit ahead of the primary disconnect. If connecting the circuit ahead of the primary disconnect would be legal, I'm would guess that it would have to be fused to isolate the circuit in the event of a short, etc.
Can any of the licenced electricians give us a read on this issue? All we need connected to the utility power source is a relay coil via a contact or two.
I know the above post is kinda old, but I just saw it. I'm not an electrician, but I believe NEC 230.82 specifies what kind of taps can be made on the line side of the service disconnect. I found the list somewhere when I was researching whether or not my installer broke the NEC code when he put the genset battery charger hot wire on one of the line side lugs.