generator transfer switch

It was above the refrigerator in the 120v breaker, 12v fuse panel. we had to remove all the breakers and the buss bar, and the fuse holders to get to the generator transfer switch. The neutral side had burned up.
It doesn't seem to me that one should ever have to tear apart an electrical panel to get to anything. I really wonder about some of the engineering today.

Thanks for the help,
Dusty