Forum Discussion
RoyB
Mar 18, 2017Explorer II
I do this all the time at a campground with my 30A Trailer plugged into the 30A service plug and an extension cord running my electric heater in the trailer plugged into the 20A pedestal service.
On the 30A side my trailer can pull up to 30A before tripping the pedestal 30A breaker. On the extension cord side I can draw up to the 20A service before tripping the pedestal 20A breaker.
So I guess you can say I an hooked to a total of 50AMP service here...

Using this type of adapter would not be a good idea being plugged into a 50A Service connector at the site pedestal. The 20A plug used here would be fed by a 50A breaker in the site pedestal...

Doing this at your house using one of these type 30A(M)-20A(M) to 50A(F) adapter may be a different story... You would think one of your 50A zones in your trailer would only get a 30A service and the other 50A zone would get a 20A service using one of these adapters...
The adapters would be very illegal if the HOT side is a MALE PLUG that someone could touch when energized... Using this on a trailer like the Class C where you have an on-board generator might do this to an adapter plugged into the shore power connection. It should be protected from this by using a switchover contactor on the RV side but I would double check using a multi-meter just to be sure...

Roy Ken
On the 30A side my trailer can pull up to 30A before tripping the pedestal 30A breaker. On the extension cord side I can draw up to the 20A service before tripping the pedestal 20A breaker.
So I guess you can say I an hooked to a total of 50AMP service here...

Using this type of adapter would not be a good idea being plugged into a 50A Service connector at the site pedestal. The 20A plug used here would be fed by a 50A breaker in the site pedestal...

Doing this at your house using one of these type 30A(M)-20A(M) to 50A(F) adapter may be a different story... You would think one of your 50A zones in your trailer would only get a 30A service and the other 50A zone would get a 20A service using one of these adapters...
The adapters would be very illegal if the HOT side is a MALE PLUG that someone could touch when energized... Using this on a trailer like the Class C where you have an on-board generator might do this to an adapter plugged into the shore power connection. It should be protected from this by using a switchover contactor on the RV side but I would double check using a multi-meter just to be sure...
Roy Ken
About Technical Issues
Having RV issues? Connect with others who have been in your shoes.24,369 PostsLatest Activity: Mar 12, 2026