Redsy,
Garbage disposal is a good example, but I actually had to troubleshoot and fix a homeowners self induced problem in an old house. He had added an "instant" hot for his bathroom upstairs in an older house along with a subpanel, he neglected to separate his neutrals and grounds. Now he had overcurrent on his shower controls, got zapped everytime he was wet, kinda served him right, buuuuut, boy was that dangerous (cast iron DWV was a pretty good conductor). That was always the best 'splanation I could give for that one. [Linked Image]