This definitely went wrong for my mate yesterday. He got a call out for an RCD tripping in a shop so went to have a look, managed to fix that fairly quickly and whilst he was there they said can you have a look at our lights so he did. It was a grid ceiling with 600x600 LED panels in, and the way they were wired was with a plug/socket type affair on short leads and T-pieces. The name of the plug escapes me for now but its a flat 3 pin plug same as these.
You can get short leads with a male plug on one end and a female socket on the other you then use 3/4/5/etc way splitters like above to give you ways for the lights which obviously have a male plug fitted. We fitted loads of them the other year on shop refits, I didn't like them as you couldn't really support the cables between the lights and they just ended up on top of the grid, also they were really hard to push together and engage the clips and sometimes if you pulled them apart it broke the T-splitter instead exposing the pins.
Anyway, some of the lights weren't working (not one of our jobs by the way) so he goes into the grid ceiling to have a look, grabs one of the leads at a junction and gets a big electric shock, falls off the ladders, cuts his leg and twists his knee quite badly. Turns out that the T piece had melted and exposed the connection, probably because it was never fully pushed together. He's been to A&E today and they said he has probably damaged his ligaments.
So not too sure who is at fault really, I suppose by the book he should have turned the power off, locked the MCB off and got the barriers out, tested dead etc etc but when you are fault finding like that you really need to do it live in order to find where the live bit ends and the fault begins, which he certainly did do yesterday. Or is the shop at fault for letting someone near their dangerous electrics? I'm not too sure how the shock was that bad but he reckons he thought his number was up and can't remember falling off the ladders, just getting up off the floor. He was on fibreglass steps, boots and carpet so it wasn't that, must have been the ceiling grid that was earthed, either that or it just wen't between the pins in the plug via his hand and he was being over dramatic about the shock to justify falling off the ladders.