I’m pretty sure I’ve found the problem, should have though of this earlier I have a 30 ‘ extension cord I made up and it’s smaller wire then what’s on the coach. I Backed the coach up as far as I could and hooked it straight to the pedestal and the watch dog ran both ac units and most of the lights all day with no problems, so I surmises that the wire size difference wouldn’t care the full load of the 50 Amps.
We will learn this Motorhome Ownership, thanks to all who have helped.