I have a Briggs Storm Responder 5.5 KW, with my lighting load and a ice box running I start a 3-Ton Goodman GSX13036 All day long on my camp. The condenser has a kick start kit installed that is rated for up to 5Hp.
I will get a video of it..
I just put a Tri-Fuel kit on the generator so it will run on propane and methane. If the spent propane fuel does not take up to much displacement in the engine I think it still may run the A/C on the propane but not the methane.
1 gallon = 125,000 BTU
1 gallon = 91,500 BTU
1 cubic foot = 2,500 BTU
36.39 cubic feet = 1 gallon
1 cubic foot = 1,050 BTU
If I can't get the A/C unit running on the Alt Fuel I will put a larger engine on the generator frame to recover more HP when running on lower BTU fuels.
It is safe and accepted by the NEC to run a generator with no transfer switch as long as a APPROVED inter-lock kit is installed at the panel the generator is feed into, we do this all day long and make good money at it. Every job is inspected by south central planning! just search for generator interlock kit "and hit I'M FEELING LUCKY" The kit is about $150 retail and $100 if you are a dealer for them.
I have no ties to the above product other than I just use a lot of them for my customers!
If you have a AutoTransfer switch your generator must provide the same amount of power your service from the PoCo provides, Otherwise you must have a load shedding system installed. All generac nexus and briggs smart switch provide load shedding provisions.
All cables from your transfer device be it a switch or inter-locked panel must be oversized by 25%.
Your generator does not need a ground rod located next to it as long as your EGC is sized properly for the ungrounded feeder conductors running from it.
Guess I will stop now I could ramble about this for days!