Most legit licensed Electricians are BONDED just for this. Their Insurance should cover everything that has failed from their doings.
Now if your Brother-in-Law was the Electrician doing this on the side then all bets are off for getting any help...
Performing this simple AC VOLTMETER test would have caught the mistake wiring right away...
Pictorials from GOOGLE IMAGES
Even though you see 240VAC listed in the 50AMP pictorial keep in mind the 50AMP Trailers normally have two 50AMP 120VAC ZONES and only the very high end trailers would tap into the 240VAC usually for the washer/Dryer combos...
RV 50AMP Distribution
RV 30AMP Distribution
Drawings by DMBRUSS
Alot of us probably would do just what you did and turn it ON to see if all works ok. In hindsight you probably should have tested the circuit yourself first before plugging into it just like we do before plugging into the 30A and 50A pedestals at the campgrounds...
Since you are looking at thousands of dollars here I most definitely would let the professionals handle everything..
Just my thoughts
Roy Ken
