I'm still working at the place mentioned earlier -- I was only there for 3 months (actually one day less than 3 month, I know this because the recruiter only got his commission when I was there for at least three months, if I'd know this I would have stuck it out for another few days), but have more "funny" stories from this place than any other, anyway, onto the story:
One of the server rooms becomes unusable and needs to be rebuilt[0], so everything needs to be migrated out of the existing room and into new space -- this includes a large APC Symmetra UPS. We shut down the UPS and pull all of the batteries out of both it and the expansion shelves so that we can move it with a pallet lift. We move everything into the new space and its time to put the UPS back together. I quickly decide that lifting large numbers of heavy batteries into the shelves is not fun, so I show the random helper dude what to do... "You pick up this big, heavy thing and put in into this cubbyhole type spot, then you connect this large connector and slide the battery back, lather, rinse, repeat...".
I watch him do the first one and he seems to have it figured out... I wander off to go hook up some fiber or something and peer down the corridor every now and then to make sure he still has this under control. Surprisingly enough he is managing ok and hasn't wandered off to take a nap or anything. He gets down to the last few batteries and seems to be having some issues, but I figure he'll work it out, so I carry on with what I am doing... I peer down the corridor again and he is sitting on the floor with his back braced against something, pushing the battery into place with his feet... "Whoa, this can't be good", I think, just as there is a LARGE bang, a big flash and much smoke and fire....
Turns out that for the last battery he managed to get the cables caught between the side if the battery and the side of the (sheet-metal) case. When it didn't just slide easily back, he pushed it really hard and the edge of the case chomped through the cable creating a dead short -- this literally vaporized a crescent of metal from the case around 5 inches in radius, flung bits of molten case and battery leads all over the place and ignited the cardboard that we put on the pallet to soften it...
Much hilarity ensues...
[0]: Have you ever noticed that places that use gas fire suppression systems either have doors that open outwards and / or big dampers (like http://www.c-sgroup.com/product_home.php?section=explovent&page=3) ? Ever wonder why? :-)