[SteveC7010]

Remember that you want to pull from two separate 30 amp 110vac connections and feed them into one 220 vac 50 amp connection to feed the trailer. Electricians correct me if I am wrong, but I am pretty darned sure that you have to pull from each side of the branch to properly have 50 amp 220 vac.

Here's what I am trying to say: 220 vac is actually 110 vac on a left leg and 110 vac on a right leg with a single common and a single ground. To pull 110 vac, you tap either the left or the right leg plus ground and common. To pull 220 vac, you have to have the left and the right plus common and ground. I do not believe that you can tap one side or the other twice and get 220 vac.

Look at a residential electric panel. All the 110 vac breakers are connected to either the left or the right hot buss bars. All the 220 vac breakers straddle and connect to both buss bars. None of the 220 vac breakers connect twice to one buss bar and not at all to the other.

The only way to safely do this is to verify that you are plugging one 30 amp connection into the left leg and the other into the right leg of the same 50 amp 220 vac line. Without the proper electrician's test equipment, you will have a difficult time verifying this. Given the fact that many campgrounds are poorly wired at best, this is risky business all around.

If I was in your situation and truly needed 50 amp 220vac, I'd approach the campground management and ask them to provide it or....

Bite the bullet and separate my second air conditioner from the regular TT wiring and connect it up to its own breaker box and a 20 amp shoreline. That way, I can connect the trailer to one 30 amp hookup and the 2nd a/c to a 20 or 30 amp outlet. It is also possible to wire your rig so that the 2nd a/c's shoreline can be plugged into a special connection on the trailer when you are properly hooked up to a 50 amp 220 vac RV connection. The cost to do all that that is probably less than the cost of trying to do what you propose. And it would be a whole lot safer.