This is not a WB part but it is a good one to see anyway.
I removed this ground lug from the back of a Citation over the weekend.
It was cleaned a while back and never resealed when reinstalled.
It is the main ground for the Battery contactor, I was called to replace the battery because the airplane would not start. Even with a power cart.
The bolt rusted, the bracket corroded, and the high amperage heated the bracket enough to melt the aluminum and weld it onto the bolt head.
Keep your grounds clean, and seal them with PRC!