Thanks everyone!,
Dan, you say some have put their proctor between transfer switch and load? Even though I don't have a generator, would it matter or be best too?
A few more questions, Do you think I could put a plug (on the end of the pre wired gen box) up front, and if power were to go off, l could just plug portable gen into that plug? If power were to come on while gen was running, would it transfer?
The transfer switch is a potential point of failure, even without a generator. So in my opinion the best placement of the EMS would be after the transfer switch.
You can install a plug or receptacle at the junction box in the front compartment. The wiring in the junction box is for 2 hot legs, same as in the transfer switch. If the generator has only one hot leg (typical for a small generator), you'll need to tie both hot legs of the junction box wiring to the single hot wire of the generator. That's the same as what happens if you plug your 50 amp shore power cord into a 30 amp receptacle. The adapter ties the 2 hot legs to the single hot leg.
As long as the transfer switch sees 120V on L1, it will activate the contactors inside the transfer switch. If you've tied the wiring correctly, the switch will activate and both legs going to the circuit breaker panel will have power. If you have power to 1/2 of the outlets, or if the transfer switch doesn't activate, you may have not tied the power lines correctly.
Things to watch for: 1) You don't want to have plugs that could be energized when unplugged. Safety hazard. 2) You may have to provide a bond between neutral and ground at the generator. The transfer switch may or may not do this for you. If power from the generator doesn't get through the EMS, you should read
this article.