Get the electrician back in and apply Clue with a Megga.

Those sort of oddities in wiring aren't that unusual, especially with stock partitioning used for offices.

We had one where there was a light switch inside the office controlling lights outside of it, but to turn the lights in the office on you had to walk out to another switch - we never did get that one fixed before they removed the separate office in a corporate "rearrangement" (it was back again a couple of years later).

Ah. Portioning in offices which doesn’t match the lighting circuits and switching.

Always good for a laugh, like the company I worked at a few years ago who created a new meeting room, installed a projector and screen, but left the lighting circuits shared with a large chunk of the office area it had been carved out of resulting in massive shouting matches and spectacular toy ejections when people in the meeting room wanted the lights down so their PowerPoint shows looked nice on the big projection screen and those of us outside it wanted to be able to see, well, anything really…

Hours of fun testing if mate is paying attention when doing an insulation resistance survey...

That rarely ends well.

It's pretty much standard practice in the US from what I've seen. They tend not to have wiring in the ceiling in favour of some sockets connected to the wall switches into which lamps are plugged.

I remember back in the 70s my grandma still had extension cables with a lighting bayonet connector at one end and a round pin mains socket at the other.

Considering she was still using round pin plugs and sockets then, I was surprised to see that BS1363 goes all the way back to 1947.

I am constantly dodging the power outlets that are connected to the lighting system since the LED lighting came into our building... the electricians\company that brought them didn't realize we had projectors and speakers connected to the groups they pinched for this project. Only took us about 2 minutes to figure out the dodgy work and by pass it.

My local petrol station has a ghost called "Naughty Nigel". He's the one that stops things working for a fuel buying petson but allows it to work perfectly for an employee -- as witnessed last night with a fuel pump and card reader (with a long queue behind of course) :-)

And go wrong they did. At a most inconvenient time.

There's any other time in such situations???

How on earth did they manage to take a spur off the lighting loop?

I mean I've seen it done by Weekend warriors and day 1 apprentices but in a factory, you usually have sparkys who can at least tell by the wire guage they are doing something dumb....

Tale doesn't quite add up..., most plausible explanation is that there was a fused spur switch next to light switch and eco foreman got a bit flick happy

Because US...

They don't have the same separation that we do in the UK between lighting and power.

Just like the olden days when you have installed a new automation system and the build and FAT team forgot to disable hibernation and sleep modes.

That awful sound of motors and pumps slowing down, and tssst as valves open and close...... 10 mins after you left the rack room.

Reminds me of one from many years back when loads of fuel pumps stopped working on the same day.

Engineer was sent out to investigate, plugged in a keyboard and screen* to see a dialog box along the lines of "Daylight saving has ended" with an "OK" button - turns out Windows 95 wasn't really up to being used as an embedded OS...

*or equivalent

... or anything else

In a previous company, I was shocked (literally) that, wearing a big wool jumper, and sport shoes, I had constant electrical shocks when touching the coffee machine.

After a while, I was grounding myself to the stove of the kitchen before even approaching the coffee machine.

Didn't work, still a 100 V or similar big electrical shock ... WTF ?

Yep, you guessed it correctly, the stove was plugged to an outlet belonging to another distinct part of the building, apparently not of the same generation.

And yes, the electricians neglected connecting the 2 buildings grounds together. There was dozens of volts between the grounds of the 2 buildings !

... or as we were told at a seminar on grounding/earthing practices...

"There is no such thing as earth potential"

repeated after each example of things that can (will) go wrong.

I had a small customer in the Caribbean many years ago that had a problem with SQL back ups not running. They were scheduled to run at night, same as every other customer. Turned out they didn't have mains power, they ran on a generator - which they shut down every night when they finished work. Normally our implementation engineers are on site till the place closes, so he should have seen it... however I'm guessing the call of paradise was stronger than the desire to work stupid hours.

An old story from the jargon file:

http://www.catb.org/jargon/html/magic-story.html

First saw that {mmfty}{mmmf} years ago - never forgot it!

Way back when...

We were updating from Win XP to 7, and to lesse the inconvinience, we were updating in place.

Most of the time this worked just fine.

And then, we hade one site, where the road warriors where called in to, to get their laptops updated overnight. And a lot of them failed at various times in the evening. Somewhere between 19:15 and 20:20 or something like that.

OK, image as new, and hear the users complain. This happened with a lot, but not all of the laptops whenever we tried to mass update at that site.

Turns out that as a eco initiative, the desks were setup with regular and green outlets. The green outlets where ment for desk lamps, phone chargers and such, and to power to these would be cut when the office was empty. Fair enough. And the laptops connected to these outlets would then lose power, but since they had "buildt in UPS", they would go down at some later time, depending on the state of the battery.