No power to light suddenly

Kagawa

Hi All,

The light in my dinning room just stopped working a couple of days ago and I thought it was just a bulb, but when I replaced the bulb still no joy. Anyway I removed the switch and checked to see if there was any current going to the common and there wasn't. I then changed the switch and still nothing, wasn't expecting anything either. I also checked if there was any current going to the ceiling rose light and there isn't.

I changed a few old switches upstairs last week but everything is working fine up there, I assume they can't be connected as they are on a different circuit anyway. It was a couple of light switches controlling two upstairs hall lights.

I am going to call an electrician tomorrow anyway but I just though somebody here would have some ideas on what might be going on. From my basic understanding of how these lights are wired, the from the lights in the next room. But all the other lights downstairs are working fine.

Thanks for any ideas people may have.

aido79

Kagawa wrote: »

Hi All,

The light in my dinning room just stopped working a couple of days ago and I thought it was just a bulb, but when I replaced the bulb still no joy. Anyway I removed the switch and checked to see if there was any current going to the common and there wasn't. I then changed the switch and still nothing, wasn't expecting anything either. I also checked if there was any current going to the ceiling rose light and there isn't.

I changed a few old switches upstairs last week but everything is working fine up there, I assume they can't be connected as they are on a different circuit anyway. It was a couple of light switches controlling two upstairs hall lights.

I am going to call an electrician tomorrow anyway but I just though somebody here would have some ideas on what might be going on. From my basic understanding of how these lights are wired, the from the lights in the next room. But all the other lights downstairs are working fine.

Thanks for any ideas people may have.

Is there a transformer for the light?

When you say you checked for current what did you use? (you're actually checking for voltage not current)

Has the light in the dining room worked since you changed the switches upstairs and is it definitely on a different circuit breaker from the lights downstairs?

punisher5112

Possible when you were at it upstairs you pulled a cable or didn't re connect right.

TheChizler

What do you mean by checking the common for current? Did you check for current with a current clamp? Which won't tell you anything when the lights aren't on. Or do you mean voltage? Cause the voltage between the common/neutral and ground will be zero or very close to even when the lights are working. You need to be checking voltage at the live wire, between that and neutral and it and ground to get the most information you can.

mickdw

Turn on everything upstairs that you worked on and then check to see if light is working downstairs.

Kagawa

aido79 wrote: »

Is there a transformer for the light?

When you say you checked for current what did you use? (you're actually checking for voltage not current)

Has the light in the dining room worked since you changed the switches upstairs and is it definitely on a different circuit breaker from the lights downstairs?

Hi Aido, no, its just a ceiling rose light, a single brown, blue and earth cable. I checked with a phase tester at both switch and the light and it didn't light for either. I did the same on the same type of light in a different room and the it lights up. The light are on a different fuse in the fuse board, one for upstairs and one for downstairs.

I can't be exactly certain on when the downstairs light went as we don't use the room so i wasn't too bothered when I got to chasing the bulb.

Kagawa

mickdw wrote: »

Turn on everything upstairs that you worked on and then check to see if light is working downstairs.

Hi Mick, the light switches I changed upstairs all controlled the same light, ie. two switches controlling two hall lights, one was an intermediate switch and the other was a two way switch and i have turned on the light upstairs and then tried the dinning room light and still nothing in the dinning.

Kagawa

TheChizler wrote: »

What do you mean by checking the common for current? Did you check for current with a current clamp? Which won't tell you anything when the lights aren't on. Or do you mean voltage? Cause the voltage between the common/neutral and ground will be zero or very close to even when the lights are working. You need to be checking voltage at the live wire, between that and neutral and it and ground to get the most information you can.

Hi, i used a phase tester and it didn't light up when i touched the common screw in the switch, wether the switch was on or off.

thecribber

Kagawa wrote: »

I changed a few old switches upstairs last week but everything is working fine up there, I assume they can't be connected as they are on a different circuit anyway. It was a couple of light switches controlling two upstairs hall lights.

It's pretty much 100% the case that you caused the problem yourself when you did the switch change. Lights don't just stop working, they stop working because something electrical has changed. Double check all your changes. If you have also changed light fittings in any room in the house check these also.

Kagawa

thecribber wrote: »

It's pretty much 100% the case that you caused the problem yourself when you did the switch change. Lights don't just stop working, they stop working because something electrical has changed. Double check all your changes. If you have also changed light fittings in any room in the house check these also.

Thanks, I was afraid of that, it seems odd to me that the hall light upstairs could be in any way connected with the dinning room light downstairs. I'll have a chat with the electrician tomorrow and he'll be able to figure out whats going on. I don't have the kit to figure this one out.

punisher5112

The live (common) could well be linked.

Neutral tend to be and if not linked right can cause issues elsewhere.


Quite possible you pulled a wire or even possible the linking wire isn't in tight enough or the sheath is stopping a connection.

TheChizler

Kagawa wrote: »

Hi, i used a phase tester and it didn't light up when i touched the common screw in the switch, wether the switch was on or off.

I'd be checking all points on the switch in case it's wired backwards or something.

I recently discovered the outside light switch in my apartment was wired in series with the bedroom light switch, meaning the outside switch would do nothing unless the bedroom light was on. Maybe repeat the test with nearby switches on in case something similar has happened there?

CaptainCoPilot

You mention its the hall light. Im going to go out on a limb and say that you have a switch for the hall light downstairs and upstairs?

The supply for your upstairs hall light is probably coming from the downstairs lighting circuit, a live supply bridged from another switch downstairs and the neutral in the hall light could be linked to the lighting circuit upstairs. The supply for your dining room is probably coming from one of the switches in the hall circuit.

My guess, focus on the hall switches. You might have installed the wrong switch type in that position. Could you refit the old switch and see if it works then? Are there more than two switches that switch on the same light and are they all working? You might need an intermediate switch rather than a 2 way.

TBH, best to call in an electrician. In worst case you could get a new supply for the dining room from another room downstairs, but a competent electrician should be able to figure it out.

Kagawa

CaptainCoPilot wrote: »

You mention its the hall light. Im going to go out on a limb and say that you have a switch for the hall light downstairs and upstairs?

The supply for your upstairs hall light is probably coming from the downstairs lighting circuit, a live supply bridged from another switch downstairs and the neutral in the hall light could be linked to the lighting circuit upstairs. The supply for your dining room is probably coming from one of the switches in the hall circuit.

My guess, focus on the hall switches. You might have installed the wrong switch type in that position. Could you refit the old switch and see if it works then? Are there more than two switches that switch on the same light and are they all working? You might need an intermediate switch rather than a 2 way.

TBH, best to call in an electrician. In worst case you could get a new supply for the dining room from another room downstairs, but a competent electrician should be able to figure it out.

Hi, yes, there are two switches upstairs and one downstairs, the switches upstairs and downstairs all function correctly. I didn't go near the downstairs switch. One of the switches upstairs is an intermediate switch, and i did have a look but when I changed the current configuration the switches upstairs didn't work. The electrician will be around in the next couple of days anyway. Thanks for the suggestions though.

Is it possible the problem is with the intermediate switch upstairs or the other three way switch? One of the three way switches has three wires going to the common on that switch, is this common?