During the early hours of this morning I was woken by the thunder storm.
Then I noticed the extractor fan in the bathroom had started up.
I got up to check and the switch for it was still in the off position.
I know that it runs on for ten minutes after the switch is turned off and presume there is some kind of capacitor in there that allows it to do this.
But how did it start up on it’s own directly after the first lightning flash?

I can’t be completely sure but if there is a capacitor it is just for timing, not providing the energy for the fan. That will come from the mains as normal.  Lightning creates a big electromagnetic pulse so I’m guessing that was enough to trigger the circuit that drives the fan and once going it will keep going until it times out.  You probably don’t notice if your LED lights blip on briefly but because the fan has something designed to keep it on for a few mins after you will see it

Just to add to the question.
The fan in the other bathroom that’s exactly the same and about 3 meters away didn’t switch on?
So though your answer kind of makes sense it also doesn’t?

The fan has a permanent live and a switched live. When you turn on the lights, the switched live turns on. That is the signal to turn on the fan – just a signal. When you turn off the lights the fan keeps going using the permanent live for e.g. 10 minutes.

The lightning “turned on” the switched live, that’s all.

Or ghosts. But you may have to argue that one with Professor Brian Cox.

The lightning “turned on” the switched live, that’s all.

That’s kind of what I thought but why did it turn one fan on and not the other?

why did it turn one fan on and not the other?

Possibly a combination of tolerances and small factors like the wiring for one circuit being oriented one direction compared to the other – acting like arials – electromagnetic radiation is directional – well, arials are anyway.

Or your ghost has a favourite bathroom.

Or your ghost has a favourite bathroom.

I did wander where that smell was coming from.🤣

Coincidence. Family member or a ghost

Hello.

Apologies to the OP for the hijack but I’ve got two problems.
First I can’t start new threads when posting from my telephone, I don’t know why, been like that for ages. I currently can’t post from my laptop, where I can make new threads, as I have no electricity on at present (yes, it has a battery but the router is off) Anyway, I’ve found an electrics related thread to hijack and ask the question I wanted to ask:
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I’m just changing a light switch and I’ve got myself confused.
It’s a four core cable, red, blue, yellow, bare (earth)
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The old switch had four connections, marked 1 yellow, 1 red, 2 blue, 2 empty and the earth going to the back box.
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The new switch only has three connections L1, L2 and com with a separate one for the earth.

Earth is obvious. Is it L1 red, L2 yellow and blue com or will I kill myself if I do that?

Thanks

Nifty – lucky git!

Just noticed that the red on the old switch said 1C, not just 1. That and the empty 2 both say intermediate too if that helps

Just noticed that the red on the old switch said 1C, not just 1.

If that is true then it is possible that your first set of colours are wrong :(.   It sounds like this switch is one of a pair of switches used to turn a light off from two locations.   If so I would look at the other switch to get a clue as to what is going on

Correct, it is one of a pair, it’s the upstairs one of the stairs lights.
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Downstairs has a switch more like the new one for upstairs.
L1 blue, L2 yellow, com red and earth to the back box. Do I just replicate that upstairs?

Have either of the switches got a second cable?

Anyway, there’s a link here that might help, but there are different ways of connecting two-way lighting. Just remember that anything, regardless of colour, could be live so get proper help if you’re unsure
2-way diagram

No, no second cable to either, it’s a bit odd. It all worked fine until I took it apart yesterday,that’ll teach me.
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From that link, the bottom one in both fig2 and fig3 look exactly like my downstairs. However, my downstairs doesn’t have that second cable which it shows in the top one.
There is a 240v/12v converter in the system, presumably the second cable will be going to that?

Is there another switch somewhere, midway on a landing perhaps?

No, it’s just those two.
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My current approach is trying to find a switch which is exactly the same as the one which has come off so that I can just copy how it was but Google doesn’t like to show the pictures of the backs of switches. Might have to go into town and have a look at B&Q, although if they haven’t then it’s Edinburgh for any other electrical shops

Hmm. No new lightswitches like the old one. I wonder if that’s an old discontinued design? House last renovated in 1987, it could have been installed then

Post some pics

Fingers crossed this works!
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Upstairs as was
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Old white switch and new grey switch
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Upstairs as was. Wall now demolished and switch broken🙈
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Downstairs, which I haven’t fiddled with

Almost worked, it’s just messed up the captions.
Edit
Fixed now, all labeled correctly

I can’t see the detail, what are the terminals marked as on the switch with four terminals?

Into your new switch, start with red in common, yellow L1, blue L2 and an Earth lead from the box to the E terminal on the screw hole. There’s a junction box somewhere where the ends of both those cables go then another cable goes to the light. All the cores are meant to be live dependent on orientation of the switch’s so if the above doesn’t work the worst that’ll happen is the light will stay on or one of the switches won’t do anything then it’s trial and error (or a tester) to work out the right connections

The old switch had four connections, marked 1 yellow, 1C red, 2 blue, 2 empty and the earth going to the back box.
1C red and the 2 empty are both marked intermediate.
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Downstairs is L1 blue, L2 yellow, Com red and earth to the back box.
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Thanks for your time by the way, much appreciated!

Hope you’re sorted now. The reason that the new switch is different to the original is that the original is an intermediate switch that can be used in a two or three-way switched system, the new one is two-way switch
Some intermediate switches are marked L1, L1, L2 and L2 but they do the same job

Looks like me and Mark had a crossed post, just checked back now to see what to do.
Going to do what Mark says, so thank you very much, and many thanks to Timba for teasing the right info out of me and then getting beaten to it at the last minute!
Here goes…

Perfect! Thanks guys.
If either of you are at SSUK or the Kielder Chiller it’ll be my round all night!