One December, I walked into the cottage that we had purchased the previous spring - to discover the ceiling on the floor and everything drenched and ruined. What the heck???????
As our builder tore things apart to do a rebuild, he discovered a water pipe that went through the attic and was wrapped in heat tape. It was laying under a layer of fiberglass insulation, so explains why we weren't aware of it. It seems the heat tape shorted out and started a fire; the fire melted the solder at a pipe joint, so the pipe came apart and flooded the house (putting out the fire). Eventually, the water shorted out the pump circuit breaker, shutting it off.
I have no idea how old that heat tape was - it could have been correctly installed and just shorted out due to old age and brittleness?