I've solved some pretty complex electrical and electronic problems, but I don't even know where to start on this.

Thanks

 

Is there a tesla coil in the building?

 

We had a similar problem after the electricity company swapped line and neutral to the house. It means that the switch disconnects the neutral but leaves the line still connected to the tube. I don't know why that makes the light flicker even when switched off but that's what they did. And just as well too as that is not a safe condition and the flickering told me there was a problem and I could tell what had happened. The electric company were round very quickly to put it right.

 

Is there a tesla coil in the building?

No, and I forgot to mention that the flickering is infrequent. It flickers and then doesn't for anywhere between a few minutes and a few hours and then flickers again—maybe once, maybe a bunch of times.

Totally random.

 

No, and I forgot to mention that the flickering is infrequent. It flickers and then doesn't for anywhere between a few minutes and a few hours and then flickers again—maybe once, maybe a bunch of times.

Totally random.

Weird. Is it just one light or lights all over?

 

Check that line and neutral are the right way round and that the switch is wired to disconnect the line.

 

Weird. Is it just one light or lights all over?

It's been reported to me that it's in this one guy's room but I can't check it until the morning.

It's not my responsibility anyway, but their maintenance electrician can't solve it and they think I'm a genius so they asked if I'd help.

For the record, I'm not a genius.

 

Check that line and neutral are the right way round and that the switch is wired to disconnect the line.

Will do. It's a mobile camp, so every module is unplugged, moved, and then plugged back in every 2-4 weeks or so.

As soon as I can get access to it, I'll check the line and neutral.

See, I was thinking that it had something to do with capacitors discharging or something. This kind of thing isn't my forté: I work on PLCs, motor starters, PCI and that kind of thing.

 

The symptoms you describe are the same as I saw so it's definitely worth testing.

 

It's been reported to me that it's in this one guy's room but I can't check it until the morning.
.

Find out if he was smoking anything?
Max.

 

You are looking at an energy discharge of some type. If the line is properly connected, then I would look for sources of static in the area.

 

Had something similar .Flouro light would not switch off. Pulled cable from switch to light and ran new cable. Found some sort of rodent had chewed cable causing a partial short and intermittent tracking due to cable charring.

 

The metal portion of the fixture near the bulb needs to be checked. Make sure it's a ground potential.

 

Ha ! I noticed this in my wife room in her home island.
All the ceiling lights flicker randomly.
I found it pretty amusing to watch them as I sleep.
Did not care to find problem though, but I was pestered to look into it.
How can I look into it when I am on vacation

 

Most common cause is from having having an illuminated light switch on the circuit feeding the lights. The tiny neon bulb slowly charges up the capacitors in the lights solid state power supplies until they momentarily turn on and discharge themselves.

Depending on the amount of HF noise and voltage spikes the rate the neon bulb will charge up the lights power supplies will vary greatly thus making it pretty random.

Other common problems are from the lights having their supply line, after the light switch, in the same cable or conduit as the supply line to the switch or other parts of the system where simple capacitive coupling between the two wires can have a similar effect which again depending on the line voltages, spikes and high frequency harmonics of the live line that capacitive coupling energy transfer rate can vary greatly.

 

It might be EM induction. Lightening/rf. If all the wiring checks out..........tune an AM radio to a quiet part of the band.
Monitor for crack in static at time of blinking. Lightening would flicker and rf would glow.

One could hunt for rf interference with a sdr dongle too.

I have lit and modulated the glow from fluorescent bulbs with rf.