Wiring for 50amp plug

MetalGator wrote:
I just rented a storage garage for our new Class A motorhome. It came wired with a 30 amp plug but it's one of the twist type plugs that are typically seen on generators. I purchased a 30amp to 50amp adapter from Etrailer. I took my multi-meter to the garage yesterday to test the plug. I think it is wired correctly but I wanted to make sure before I plug in my new 100K+ motorhome!

If you are looking at the 50 amp plug, there are 3 vertical holes (one on top and two on the sides) and then one round ground plug. I believe the top hole is the neutral. Going from the top hole to one of the side holes, I get 117 volts. If I go from both the outside holes, I get 235 volts. I believe this is correct but can someone please confirm?

Thanks,
Burch

I am not an electrician, but it's my understanding that a properly wired 30 AMP RV receptacle has 1 hot (L1) a neutral and a ground. It should be 120 v. Plugging in an adapter, it would feed the L1 across the 2 hots on the 50 RV outlet. I don't see how you can measure 235 volts across those lines as the adapter is just splitting the L1 and you don't have an L1 and L2 at differnt phases to provide the 235v... I'm looking for an explanation !