transfer switch burned up

Around 4 am on Wednesday, i woke up because i heard the transfer switch and surge guard relay trip, then the following noise from the inverter, then the power tripped back on, then right back off.

then silence and i fell back to sleep
I woke up a few hrs later to the odd noise from the heater as in its was not running normal speed.
like a deer in traffic i quickly checked the surge guard panel and it was dark,
the 12v panel was down to 9 volts and flickering.
i tried the genny and she started but no engagement of electrical load.
so i shut it off and checked the power panel in the rv port to see if the 50's had tripped, by now i am dressed
no tripped breakers.

now I am concerned...and click the surge guard came back on and clearly shows we have power available for use...........
but still no secondary click of the transfers switch.
now i have donned a thick coat, crunched throw the snow and open up the power cord panel...it stunk
so i quickly killed power and then opened up the transfer switch..
yep it was burned up and caused my pucker factor to increase.

ordered a new upgraded surge guard transfer switch, which arrived this morning..thank goodness for over night AIR freight.
I had bypassed the transfer switch and was able to get power to the coach, and now the rebuild continues
tomorrow i am replacing the entire main coach line to the circuit breaker box, to be safe, something caused 6 or so inches of insulation on the white return line to melt.....

so please check your transfer switch for corrosion, as i suspect this is what caused the failure.
plus the factory installed switch had 10 gauge wires inside vice the 6 on the surgeguard
so it was nominal at best
more pics tomorrow when i am all done

what gets me is an am anal retentive at checking wiring lugs for tq and corrosion.

Thanks for the advice. I'll be checking. Sorry for your problem but I suspect it could have been much worse and you are lucky you have the skills to deal with it.

Glad you caught the problem before it became a disaster. Thanks for the heads up!

Update
i installed a new transfer switch made by surgeguard and my existing surgeguard checked out ok so its back in service
i did re-route my main line from the transfer switch to the main circuit breaker box, and cu tout the part with melted insulation, which thankfully was limited to the inside of the first transfer switch, i still cut out almost 4 feet of excess and cleaned up a the internal wire routing .
we dissected the old switch and it looks like the neutral wire failed on the switch and subsequently placed the neutral straight to HOT, and then melted down with poof.
put on a new shore power cable as well for good measure