Changing a light switch

Profiler

Hi All,

First time poster here, I've had a look over the common topics, forum charter and last 23 pages and can't see a post on this specific topic so forgive me if I am asking a question answered already.

The light switch in my kitchen has stopped working. By that I mean when I press the elevated plastic white rectangle I physically can not push it down into the on position. It feels as if something is blocking it.

Wednesday evening I noticed it was requiring more force than usual to switch it on however yesterday evening I simply could not flick the switch to on despite applying relatively a lot of force.

I'm not too DIY savvy however I've done a few bits about the house. However nothing involving electricity so I'm more than a bit cautious.

My intention at the moment is to buy a new light switch unit in the local hardware store and attempt to change the switch myself.

I know that making sure the power off is the first most important thing and I can do that.

So can anyone advise if this is relatively simple job or should I not attempt and just call an electrician?

Cheers, P.

Jennieflower

Its very easy to fit a new switch & surround. I totally busted mine, while fitting shelves, anyway, I went and bought a new one, they are cheap enough, and just fitted it. Its very easy, just remember to turn off the main switch on the esb box, so u don't get fried. I feel your better off replacing the whole switch then messing around.

North West

Hi Profiler

It's a simple job.
Turn off the power.
Loosen off two screws on switch.
Pull out switch you will see 2 wires connected to the back.
Get your new switch and put the wires into new switch exactly as you took them from the old switch.
Leave switch loose for a moment and turn on power.
Put light switch on see it works properly.
Put new switch back on and tighten screws.

all done
North West

Profiler

Thanks guys, Will give it a try tomorrow!

Found a wee spanner in the works.

In so far as that the fuse box has a list of fuses one of which is marked "lights" when I switched it off the lights in the bathroom and the lounge both stayed on :rolleyes:

Then when I flicked the fuse marked "kitchen" the radio and microwave both still had power :rolleyes::rolleyes:

Still I'm sure if I flick the main fuse and knock off all power I'll be safe to work away.

indie armada

you might have two or more wires at the switch, mark them as you remove them from the switch. the switch will have com....l1.....l2.
if you have two wires at the swicth then use com and l1. if there are 3 wires it means you have two way switching so just fit the cables like for like and you should be ok.
if your anywhere near finglas gimme a pm and ill give ye a switch.:)

exaisle

Buy yourself a phase tester so that when you switch fuses/circuit breakers off, you can double check at the actual fitting that there's no power connected. Most single throw light switches will have three connections....generally marked "COM", "L1" and "L2". WHen you take the old switch off the wall, make a note of where the wires are connected and connect them one by one to the corresponding connections on the new switch so that you dont have any more than one wire exposed at any time.

Finally....if at any point you get stuck. Leave things as they are and get somebody who knows what theyre doing. Anybody with a basic knowledge of DIY should be able to help.

@indie armada- sorry to repeat what youve said +1
I was typing as you were posting!

mattjack

hi,
when changing your switch,please make sure all your connections are tightened up properly using an appropriate sized screwdriver, failure to tighten connections may cause arcing, which may in turn cause a fire,believe me.....if you are unsure call an electrician, twice in the last month I,ve seen problems caused by bad connections/terminations.All the advice you,ve been given is good... but if you got any doubts ..don,t do it yourself.

Profiler

Hi thanks for all the advice.

This morning I switched off all the power and unscrewed the two main screws as mentioned by both indie armada & exaisle an old switch with "com" at the top and '"L1" and "L2" at the bottom. Again as predicted there were three wires going into the screw.

However I found this!



As you can see two of those wires are wired into "com" and one is going into "L1"

This is just a quick pic of the wires coming up from the wall cavity into the light fitting.



(edited to make pics smaller)

indie armada

just wire it like for like. the two going into com are supply and the wire in l1 is going to the light. so just put the two wires into com on the new switch and the other into l1. make sure there nice and tight, but dont over do it as the little brass screws have a habit of snapping if over tightened.

Profiler

Hi All,

Light switch successfully changed.

I tried wiring like for like (two wires into COM and one into L1) but when I went and switched back on power it tripped immediately.

So I wired one of the wires which was previously going into COM into L2 and all is working fine.

I took mattjack's advice and was careful to wire everything up nice and tight (but not over tight) as I want nothing arcing.

Thanks all for the advice, pointers and help, it's much appreciated

indie armada

check your other lights, cause that doesnt sound right. if you have two wires in com to begin with it means that one of those wires is feeding the switch and the other is to carry the power to the next point. the third wire in l1 is going to the light, so when you switch the switch com is giving power to l1 therefore giving power to the light.

Profiler

indie armada wrote: »

check your other lights, cause that doesnt sound right. if you have two wires in com to begin with it means that one of those wires is feeding the switch and the other is to carry the power to the next point. the third wire in l1 is going to the light, so when you switch the switch com is giving power to l1 therefore giving power to the light.

OK, I did that I checked them all (bathroom, Bed 1, Bed 2, Utility and both lounge lights) and all work while the Kitchen light is both off and on

indie armada

when you switch on that switch now, you are connecting com and l1 to bring on the light, at the same time you are disconnecting com and l2 so what ever the wire in l2 is goin to you are disconnecting it when you switch on the light.
there could be a short between the blue and brown or the brown and green wires at the switch causing the mcb to trip.

ShamFeen

That wire you put into l2 if it's not a loop feed for other lights it could be going to an outside p.i.r, photocell or even smokies.

Profiler

indie armada wrote: »

when you switch on that switch now, you are connecting com and l1 to bring on the light, at the same time you are disconnecting com and l2 so what ever the wire in l2 is goin to you are disconnecting it when you switch on the light.
there could be a short between the blue and brown or the brown and green wires at the switch causing the mcb to trip.

Right, what I am going to do is disconnect it all .

Is it worth while trying again to wire two into COM.

Or should I just bite the bullet and call in an electrician.

indie armada

Profiler wrote: »

Right, what I am going to do is disconnect it all .

Is it worth while trying again to wire two into COM.

Or should I just bite the bullet and call in an electrician.

yes if your comfortable doing it. also check the insulation of the other cables to make sure they didnt get pinched when you were refitting the switch the first time. if you see any of the other wires damaged or the isulation split, cover with some insulation tape and refit the switch then.

ps... the cables can also get damaged when refitting the screws that hold the switch to the wall, just make sure the wires are out of the way of the screws when re-fitting.

Profiler

indie armada wrote: »

yes if your comfortable doing it. also check the insulation of the other cables to make sure they didnt get pinched when you were refitting the switch the first time. if you see any of the other wires damaged or the isulation split, cover with some insulation tape and refit the switch then.

ps... the cables can also get damaged when refitting the screws that hold the switch to the wall, just make sure the wires are out of the way of the screws when re-fitting.

OK, I re-wired the switch. The two original wires are now in COM and the one wire which was in L1 before is now in L1 in the new switch.

I tested and it all works fine, it did trip the MCB but I had a look again and tried it once more and no problems.

Thanks for the advice indie armada I really appreciate it.

(edit)

I just took apart the old switch out of curiosity to see if I could work out what went wrong. I took off the panel marked COM, L1, L2 lots of white plastic bit fell out, the old switch looks to my amateur eye pretty smashed up to be honest. I'm just glad there is no sign of any scorching or heat damage,

indie armada

glad ye got it sorted. another posibilty as to why it was tripping is the new switch is faulty, eventhough its a brand new switch ye can never be sure.

slimjimmc

Profiler wrote: »

OK, I re-wired the switch. The two original wires are now in COM and the one wire which was in L1 before is now in L1 in the new switch.

I tested and it all works fine, it did trip the MCB but I had a look again and tried it once more and no problems.

Thanks for the advice indie armada I really appreciate it.

(edit)

I just took apart the old switch out of curiosity to see if I could work out what went wrong. I took off the panel marked COM, L1, L2 lots of white plastic bit fell out, the old switch looks to my amateur eye pretty smashed up to be honest. I'm just glad there is no sign of any scorching or heat damage,

Replaced a 3 year old immersion switch recently for exactly the same reason. No burn out, just bits of broken plastic internals. They just don't make them like they used do .