Non-motoring > Two gang light switch Miscellaneous
Thread Author: smokie Replies: 25
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 Tue 7 May 24 17:29 
 Two gang light switch - smokie
In my kitchen there is a two gang light switch, one switches the ceiling light and the other the under-cupboard ones. There isn't a second switch for any of them. They can be switched on and off independently.

Suddenly the under-cupboard fluorescent lights don't come on. So I've switched the tubes and the starters and they all seem fine.

So I took the switch off the wall. I have no idea how it should be wired but it appears that there is a live and neutral on one side of the switch, and the live is live (i.e. if I touch it I get a shock) whereas the other side has two wires (top and bottom) which appear to go towards the fluorescent lights, and neither is live, with the switch in either position.

The switch hasn't been off the wall since it was installed years ago.

Where does the fluorescent side get its live, is it possible the actual switch has given up? Seems very unlikely to me...

EDIT: I have, btw, searched the internet for the answer and none is rally clear enough. The latest talks about using a short wire to join the two switches - mine isn't like that now (that I can see) and the whole switch gubbins is in one moulded piece which is why I wondered whether the join is done inside the switch, effectively where I can't get at it.
Last edited by: smokie on Tue 7 May 24 at 18:00
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 Tue 7 May 24 18:17 
 Two gang light switch - Terry
If there is a live feed but the output has no current irrespective of how the switch is operated, swap out the switch. Cost is only a coupe of ££. Assuming it was working correctly before, simply replicate the connections.

Inside the switch are almost certainly some small springs and contacts. Although uncommon, they can fail.
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 Tue 7 May 24 18:28 
 Two gang light switch - smokie
Thanks, that's what I was going to do but it seems such an unlikely failure!!
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 Tue 7 May 24 20:12 
 Two gang light switch - Kevin
It's odds-on that there is no Neutral in your switch box. What you think is a Neutral is more than likely the switched Live running back to the light. They do this so that they don't have to run two cables to the switch where only one conductor in each cable would be used. It means that you can't rely on the insulation colour of a conductor in lighting circuits to tell you whether it's potentially Live or not.
A good sparky should have put a piece of coloured heatshrink or tape around the end of Neutrals used as switched Live to indicate what they are but very few actually do it.

A re-think of UK domestic wiring methodology and regulations is well overdue.
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 Tue 7 May 24 22:31 
 Two gang light switch - Fullchat
If you could lay all the wiring out on a flat surface it would make sense. But the majority is hidden and as mentioned neutral colour black/blue can carry live feed.
Depending on your room layout the cupboard lighting could be taking a live from that switch (from one of the two switches to the other switch) then returning as a negative.
Your main circuits are in the ceiling. The switches are between an additional wire from the main circuit and the light fitting. A lot of this goes on behind a ceiling rose.
Sounds like the switch is fubar to me if its been working ok.
Last edited by: Fullchat on Tue 7 May 24 at 22:34
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 Tue 7 May 24 23:54 
 Two gang light switch - smokie
Oddly....

I can't really describe how it's wired because I've not yet worked it out - but I'd replaced a smart switch which controls some LEDs on top of the cupboards. The replacement has gone tits up and when I removed it the under-cupboards sprung into life. I can sort of see where it might be in the circuit but will have a better look in daylight.

Suffice to say the top of cupboard lights are temporarily out of action!!

Thanks all for your input though, much appreciated.
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 Wed 8 May 24 09:04 
 Two gang light switch - Bobby
Threads like this remind you of the limitations of forums that you can’t post photos on!
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 Wed 8 May 24 09:24 
 Two gang light switch - smokie
I thought that too! I found quite a few diagrams and animations on other sites but none looked quite the same as mine to the inexperienced eye.
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 Wed 8 May 24 10:31 
 Two gang light switch - Falkirk Bairn
>>but none looked quite the same as mine to the inexperienced eye.

I was in the same position 9 months ago.
I bought 2 new switches and got a neighbour to wire it up.
5 mins each switch - job done.

Cost?
a can of Belhaven Best.
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 Wed 8 May 24 11:36 
 Two gang light switch - Bromptonaut
Have you worked out how the switch for the cupboard top lights messed things up?

There used to be cable with two red cores specifically for the switched live function in lighting. Our previous house built in the seventies had it but not seen it since. Sparkie who did the installation here mostly tagged then with insulating tape but it's not universal.

He also used 3 core 2 way switch cabling in an imaginative(!) way on our patio light's connection in the utility.
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 Wed 8 May 24 11:46 
 Two gang light switch - smokie
Not yet though I'm not sure it'll be logical.

Without looking, I'm pretty sure the wire from the wall switch goes directly to the top of the cabinet, then a junction box sends it to each of the under cupboard lights.

I don't normally do anything fancy so I would imagine I just took another connection from the junction box to the LED switch.

The LED switch was probably faulty as it kept going offline. I didn't connect that with the perceived problem but it absolutely is. I've replaced it with another the same so will watch what happens with interest.
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 Wed 8 May 24 11:57 
 Two gang light switch - Kevin
>..so will watch what happens with interest.

Is there somewhere safe to park if we come to watch?
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 Wed 8 May 24 13:06 
 Two gang light switch - smokie
Safe? Round here? Of course LOL
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 Wed 8 May 24 13:18 
 Two gang light switch - Fursty Ferret
>> and the live is live (i.e. if I touch it I get a shock)

I don't mean to be the person who brings up the principle of "safe isolation", but that's not really how you're supposed to test.

For what it's worth, if you can touch it without yelping, swearing, leaping backwards, and learning a valuable lesson, it's not 230V. Which is actually more of a problem because it suggests you may have a significant neutral-earth fault.

RCD protection?
Last edited by: Fursty Ferret on Wed 8 May 24 at 13:19
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 Wed 8 May 24 13:41 
 Two gang light switch - smokie
:-) It took a while for someone to take the bait... :-)

I tested using my mains testing screwdriver, without undoing anything except taking the switch off the wall.

Mind you, I have sometimes changed sockets and switches without turning off the mains. and lived to tell the tale...
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 Wed 8 May 24 19:32 
 Two gang light switch - CGNorwich
Personally I would take heed of the dreadful fate of Lord Finchley

Lord Finchley tried to mend the Electric Light
Himself. It struck him dead: And serve him right!
It is the business of the wealthy man
To give employment to the artisan.
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 Wed 8 May 24 21:32 
 Two gang light switch - Robin O'Reliant
Hear lies paddy O'Sparks,
amateur electrician.

Brown to live,
Green to earth,
Blew to bits.
Last edited by: Robin O'Reliant on Wed 8 May 24 at 21:33
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 Wed 8 May 24 19:54 
 Two gang light switch - tyrednemotional

>>
>> Mind you, I have sometimes changed sockets and switches without turning off the mains. and
>> lived to tell the tale...
>>

..well, you do.......until you don't..... ;-)

I have a healthy respect for mains electrickery. At university I once touched the live side of a switch (which was off) in a piece of electronic equipment I was attempting to repair. I was sitting at a desk at the time, but ended up picking myself up from the floor/wall join at the other side of the room!
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 Wed 8 May 24 21:37 
 Two gang light switch - Runfer D'Hills
Reminds me of the story of the guy who accidentally swallowed some of the fuel he was putting into a jet fighter.
Broke wind and ended up in Tokyo…
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 Thu 9 May 24 08:00 
 Two gang light switch - tyrednemotional
I've never resorted to jet fuel, even at university. The Polish rectified spirit distilled by a friend's Grandparents in their shed came close, though! (Almost pure ethanol). Fire-water would be putting it mildly.
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 Thu 9 May 24 08:49 
 Two gang light switch - Bromptonaut
>> The Polish rectified spirit distilled by
>> a friend's Grandparents in their shed came close, though! (Almost pure ethanol).

When I first met Mrs B she was a lab assistant in a research unit at a big London Hospital. They used pure ethanol to make Punch...
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 Thu 9 May 24 09:11 
 Two gang light switch - bathtub tom
There's a sizeable Polish community in the town where I live. I suspect it's a hangover from the Polish squadrons that were around here during WW2. Back in the '70s it was an annual thing where one or two died and a few went blind from home-brewed hooch. I tried some a colleague brought in - never again. Doesn't seem to happen now, unless the numbers are insignificant compared to the drug and booze related problems.
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 Thu 9 May 24 10:45 
 Two gang light switch - Falkirk Bairn
I went to work in Saudi Arabia in1970.
Dry country so it was either £10 (£190 today)for a smuggled bottle for the real thing or Sadiqi.

The first drink I had was Sadiqi - a "friend of a colleague" made it for "her own consumption".
Large glass, contents of a small Pepsi bottle - filled to almost the brim with Sadiqi (roughly 50% proof)- never again - it tasted OK but my head was swimming & the legs were "buckling" after 1 drink.

My colleague had his bottle every week, I stuck to Pepsi and the odd bottle of homebrew.
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 Thu 9 May 24 10:28 
 Two gang light switch - VxFan
>> ..well, you do.......until you don't..... ;-)
>>
>> I have a healthy respect for mains electrickery.

It's not the volts that kills you, it's the amps.
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 Sat 11 May 24 09:57 
 Two gang light switch - Fursty Ferret

>> It's not the volts that kills you, it's the amps.
>>

Well, sort of... but if you get the voltage high enough your skin conducts quite nicely and the current flows via your skin and not your heart. It's why people survive lightning strikes with superficial burns.

The real danger from electricity tends to be in water, where you need an AC potential of just 30V in salt water to kill. This is (one of many reasons!) why swimming near a moored boat is a terrible idea, as they frequently have leakage currents through the water if there's no RCD.
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 Sat 11 May 24 12:22 
 Two gang light switch - Zero
It's volts wot jolts and mills* what kills *milliamps

The path is the killer, one hand on source, feet on return you,ll probably survive. One hand on source, the other on return, and you are history. Probably had about 5 mains shocks in my life and all the injuries have been caused by banging my hand in the jerkaway. (No oo err jokes please)
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