My biggest oh Sh#t moment happened last Thursday. Was working at a flat above a shop where I had completed a PIR a couple of months before, and in the rectifications was to bond the old gas pipes under the stairs next to the CU. One of the pipes already had a bit of 6mm on it, and I thought well if I'm doing one I might aswell upgrade the existing one while I'm at it. At this time it's about 16:45/17:00 and I thought I'd just take the 6mm out of the CU for tonight put it in a MET block with the ME and new CU earth. I didn't turn the CU off as I know now that I should have. Anyway whilst pulling it out the bottom of the CU it touched the busbar! A small-ish pop and flash of light and everything went off.
I pulled the main fuse and checked to see that the supply was still live, but it wasn't! So i headed down to the Spar shop below and explained the situation to them and they said that they had lost power to some of their fridges etc. So I opened their DB and found that a Phase had gone down...(didn't think about the main cutout fuses at their head)
So I said I'd sort it, and went up to see my client. When I got to her she said she could hear a hissing under her hall floor. I said it's probably the shops down stairs or the neighbours using the water.
It wasn't, and turned out to be a burst pipe. By this time I went down into the hair dressers also below and they had a puddle of water on the floor, I started searching for the stopcock but couldn't turn it off so phoned a plumber I know to come and sort it. In the mean time I decided it would be helpful to start digging up the concrete hall floor to expose the water pipe. (Bad idea!!) As I took the last bit of floor out a torrent of water gushed up into my face and started to flood the flat! The client had to call the fire brigade to help me to turn the water off at the road whilst I was on my knees in the hall with every conciveable towel around the hole to hold back the water as much as possible while I scooped up what I could with a jug; with my hands in the hole to stem as much of the water I could!! (I felt like the little boy whith his finger in a dyke!)
At last the fire brigade came and sorted out talking to the shop owners and finding the stopcock in the road, while I was on the phone to the electricity board (by now it's around 20:00)
The main cutout fuse in the Spar shop had blown and so I replaced it.
The reason for all of this was that when the earth touched the busbar and went pop, it did the same under the floor between the old gas pipe and a nail which was holding the water pipe in place when the place was built (about 50/60 years ago) and blew a hole in the main water pipe in to the flat!
I left that night at about 21:15 with my head in my hands and some unhappy people, I went back on the Friday to clear up and finish what I had started. My client said that Sh#t happens it's how you deal with it that makes it better and she would always ask me back to do more work.