We were called to a customer’s house for a common complaint – the electricity went out while running the vacuum cleaner. But it wasn’t the usual blown fuse or tripped circuit breaker. Instead it was a short in an upstream device box that caused a fire, fusing the wires together and destroying a receptacle in the process.
Upon inspection it was obvious what the problem was – a splice done with a crimp sleeve instead of wire nuts. Further, the splice was not taped at all so the splice was able to easily short against the bare ground wire and start a fire. We also determined that the GFCI receptacle (which is supposed to help protect you from shocks in wet areas) was wired in such a way that it would not protect any downstream receptacles. Thankfully the damage was little and we were able to fix everything (including wiring the GFCI correctly).
While we were there we did further inspection and found many other boxes with the same issue. One splice showed signs of excessive heat to the point where it melted some of the plastic on the switch. A close call that was thankfully averted. This is why wire nuts are preferred over crimp sleeves and cheap electrical tape.