Slightly different topic but related. I had a call from someone I used to work with on Sunday,
"I'm changing the bathroom light but the red sleeve fell off one of the blacks, I've put all of the reds together and all of the earths together and I have 4 blacks left. I've got the little trip on downstairs and I've touched the end of all of the blacks and got nothing?"
Me "you shouldn't really be trying to work this out live and incidentally touch them with what exactly?"
"My finger, when I get a tingle thats the switch, I used to have one of those screwdrivers with a light in it but can't find it. But how do I know if the switch is on or off"
Me "Put the phone down, turn the Circuit Breaker off and I'll be there with in the hour"
"Oh, there's no need to come over especially, I thought you might be able to talk me through what to do over the phone"
Me "I'm more concerned you might kill yourself!"
My Dad, also a spark, could only laugh.