Light not turning off?

skaif

skaif

skaif

Soldato
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Hey guys, a couple of days ago the lightswitch in the store stopped working and kept the light constantly on.
Me being the ultimate hero decided to jim'll fix it myself and broke something.

I basically took the old switch off, took out all the screws and tried to find the fault. Long story short I had to buy a new switch. No biggie, I just plug it in and away we go right?

Wrong!

New switch, same issue. The light doesn't switch off! I even tried it without the switch and flicked the breaker on, the damn light is still on! How is that even possible?!

Just to add, there are two cables coming into the switch, a black one and a red one
 
One is main live one is return wire, work out what is what, put main live in com or L1 and other wire In L2 or switch.
 
What do you mean by "store" a larder/celler/lean to in your house or shop / warehouse?

If only 2 wires at the switch it should be the only switch but anyways as above is this the only switch that controls this light or does it have a 2 way or PIR or anything else that could be faulty and jammed on?

With power off:

make sure the wires at the switch are not touching / are separated and check them for damaged insulation / any way they could be touching.

What type of light is it, pendant, batten holder etc - if metal fitting or metal base where cables enter then possible if its not earthed and no grommet used on the cable entry the metal has cut into the switch cable wires and shorted them out so be careful the whole metal body of the fitting could be live - turn power off before touching it

next step is to check the wiring there make sure it all looks ok, no insulation damaged and live touching switch live, check its dry not damp etc

next you will need a multimeter disconnect the switch cable from the light end and check for continuity between the live and the switch live on the switch cable, if cable is faulty then you should be reading a dead short / have continuity between the 2 wires in that cable

If the switch cable has a short on it then have you drilled or nailed anything into the wall near the switch where the cable may run etc?

Also worth trying to strip back the switch cable to good cable at each end, light end and switch end and test again see if that clears the fault

If nothing obvious then you will need to rewire the switch cable

If its not the switch cable then pulling the cables at the light fitting to get some slack, stripping back to good wire and reterminating them might be worth a try and can solve non obvious damaged insulation etc
 
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Ok so to answer a few questions, the store is just used for coats, storing the vacuum cleaner and some boxed kitcheny stuff.

The light looks like this:
7ntJUV1h.jpg


The switch like this, just to show both on and off make no difference:
IWKnIj0h.jpg

8Vvi3Gsh.jpg


And with no switch at all, still on!
4SXna1wh.jpg



This is the switch I am using
wpD7DQhh.jpg


I can't remember where the wires went on the original, should have taken a pic or made a note!

Help is appreciated!
 
As there are only the two wires there is no way to really wire up that switch wrong (it's a simple single pole switch), so your switch wiring skills are not at fault.

As has been said above there may be a second switch that has been knocked, or a fault in the wiring/rose that is causing it to be on all the time (or depending on where you live a chance the neighbour has a switch they don't know what it does...*).


Hardware geeks advice is very good.


*I have heard of people turning houses into flats and forgetting to move a switch from one side of what is now a dividing wall onto the other...;)
 
Well thats good!

The house is detached so can't be a neighbour, not sure why the switch isn't working as the initial problem was with the switch not the wiring. Now having taken it off and seen the light still on I'm a bit worried that theres an issue with wiring somewhere...

It's a tiny space as well and I can't see another switch! Even if there was, surely it would switch off when the switch is plugged back in? I dno...I'm off to have another look!
 
Ok, so I switched the new switch with an existing switch to make sure that wasn't a dud and it works fine. It also allowed me to take a look at the way it was wired. Black wire on top, red down low in L1.

Rewired the switch I took out test and flicked on the breaker and the same thing!

I found one of those electrical voltage testers and it lights up when in contact with both the black and red wires....what does that mean?
 
it means that the supply is live.

I think your gonna have to remove that light fitting.

turn off the breaker first but ideally turn off the main supply as it sounds like you've got a problem somewhere and take some pics of what's behind the light fitting
 
Ok removed the light fitting and have this - (there was a bunch of crap in there, old cobwebs, bits of plaster etc)
KtJLzH9h.jpg

OHm6v0dh.jpg

Both blue and brown cables where they plug into that connector show signs of life according to my screwdriver!
 
Ok cleaned it up a bit and something does not look right here.....are the cables supposed to be crossed over like this? I.E the blue one coming down next to the brown and vice versa?
T149xrrh.jpg
 
now ideally using a volt meter you should check that its the same cable at the switch end by testing the continuity but as you don't have a volt meter maybe try tugging it and see if the switch "end" moves.

theres either a joint somewhere on that cable as you have different colours both ends or that switch doesn't switch that light.

edit - just seen your edit and no they shouldn't, wire them colour to colour, your back feeding voltage down the neutral at the moment

second edit- make sure theres some kind of separation between the live and neutral aswell and its not one continuous terminal block
 
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In the photo of your switch, there's a cable to the right that goes into the ceiling...what's that?

Also there's a junction box or something between the switch and the ceiling rose, find it and it's possible the permanent live has come loose and made contact with the switched live terminal.

NoobCannon said:
edit - just seen your edit and no they shouldn't, wire them colour to colour, your back feeding voltage down the neutral at the moment
Click to expand...

"Back feeding voltage down the neutral"? That's not the issue. A cable does not know what colour it is and refuse to work if it's not mated to another of the same colour. It does not refuse to behave as a neutral unless it is coloured blue.

At worst it's mildly confusing, but it's not the issue.
 
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