Originally Posted by caper
If the adapter was to supply both legs from a 20 amp outlet there would only be 10 amps per leg. The 20 amp adapter will only supply one leg of the 50 amp service.
Caper, it also took me a little to get my head on this straight a few years back as I thought something similar.
However, this isn't necessarily the way it works. The 50 amp services are two legs (or hots) which are L1 and L2....along with a shared neutral and ground. (4 wires total). This is commonly called a 120/240 volt split phase service.
A 30/20/15 amp service is one leg (or hot) which is a L1....along with a neutral and ground. (3 wires total)
When using an adapter to plug a 50 amp into a single L1 service, what the adapter does is "shares" or jumps the single leg L1 over to the L2 line too. The neutral and ground are the same. The power is in reality shared, not split between the two legs inside the RV
Now both legs of the 50 amp service are being fed by just the L1. Both legs are powered, but just by L1. You will have power to everything in the RV......but instead of 50 amps per leg as normal (100 amps combined total), you now are going to be limited to either 30/20/15 total depending on what amp outlet you are plugged into with the adapter. There is a lot of difference between 100 amps total and either 30/20/15.
Hold on and I will find a great schematic that's been posted several times that shows this.
What can happen, is if the adapter is faulty or incorrectly wired internally, then the power isn't being jumped/shared from the L1 over onto the L2, thus anything electrical inside the RV wired on the L2 side is not being powered.