Two way lighting circuit gone wrong

[Tony Good]

I'm hoping to get a bit of expert advice on a problem I have with a friend's wiring. Initially I was asked to take a look at a three-bulb light fitting that was regularly blowing bulbs. I took the fitting down from the ceiling to check for loose wires and found that several came out from the connectors on gentle manipulation.

I re-prepared the free wire ends (they looked a bit damaged) and inserted them back to where it looked like they came from, disconnected the fitting and checked and cleaned the bulb sockets, looked like some arcing was going on arond the bulb thread.

What's most bizarre on reconnection of the fitting though is when the light is OFF the bulbs glow dimly and when it's switched ON they glow normally. It's part of a two ceiling fitting and two way switch circuit with ordinary 40w filament bulbs.

Looking at the back of the wall switch it looks like the two circuits are crossed between the switches - I just can't understand why it was wired like this and wondered if it sounds like a familiar, albeit odd, setup to anybody?

Would welcome any sensible input _thanks all.

 

[Tony Good]

Thanks for that Leesparkykent - I totally understand you skilled guys telling me to step away from the wiring. Was just trying to help out a friend with no money to get a spark in. Big mistake.

 

[sparksburnout]

Thanks for that Leesparkykent - I totally understand you skilled guys telling me to step away from the wiring. Was just trying to help out a friend with no money to get a spark in. Big mistake.

What would you have done if you could smell gas? Back to Muddy Waters again...

 

[Darkwood]

Careful don't do anything dramatic..... And can I just ask, this guys a MEMBER??? Why is he a member?

If your refering to the term EF Member under the avatar then that applies to anyone registered in the forum and is just the general basic status, staff need to assign other titles and unless we are made aware as we cannot follow every post in every thread then we sometimes rely on our regulars to report and suggest the member be better with other assigned status like DIY.

Has his introduction to the forum in his other thread clearly states he is an Electrical enthusiast with no formal qualifications then we will update his status.
Please help us if you see similar situe's by letting us know with the report button as oppose to making a brash response in the thread which helps no-one.

 

[sparksburnout]

Thanks for that Leesparkykent - I totally understand you skilled guys telling me to step away from the wiring. Was just trying to help out a friend with no money to get a spark in. Big mistake.

Is it me or was there just a touch of sarcasm in there??

 

[sparksburnout]

If your refering to the term EF Member under the avatar then that applies to anyone registered in the forum and is just the general basic status, staff need to assign other titles and unless we are made aware as we cannot follow every post in every thread then we sometimes rely on our regulars to report and suggest the member be better with other assigned status like DIY.

Has his introduction to the forum in his other thread clearly states he is an Electrical enthusiast with no formal qualifications then we will update his status.
Please help us if you see similar situe's by letting us know with the report button as oppose to making a brash response in the thread which helps no-one.

Bring back DS thats what I say, think about it.

 

[The Ghost]

Well that is a good point. This is what people do when they do not have the money to afford a tradesman, have a go. Its just unfortunate to be in such a position. Maybe post a piccy tomorrow. But please make sure the electrics is defo off! The legal position is very fraught for you if something goes wrong. Its a lesson to us all, stick to what you know and have been trained for.

 

[buzzlightyear]

I have just looked at the picture on the light fitting was the screws on the copper conductor or the pvc. sheath ?

 

[Pat H]

If you only altered the wiring in that ceiling rose then yes you have interrupted the normal L/N feed that loops from one fitting to the next. All the lights normally have live and neutral and earth fed to them from the consumer unit. Most ceiling fitting have a bus bar at one end connected to the neutral of the light flex this bus bar has the incoming Neutral and outgoing neutral (unless its the last light in the chain)
The bus bar on the other end connects to the live light flex via the switched live feed.
The center bus bar has the incoming live and outgoing live (unless its the last light in the chain) and then it also has the live feed to the switch. The complication is the cable used to go the switch is normally a twin and earth so has a live neutral and earth wire and it actually switches live so we have to indicate that the neutral is actually carrying live and we do that by putting a sleeve on each end to match the live colour.
But often that sleeve isn't present so its easy to get wires mixed up.
What's needed is to identify the incoming feed the outgoing feed and the switch wire.
Easy if you know what's what but dangerous if you don't.
Its not a big job for an electrician and I'd advise you get some help to be sure its correct and safe.

 

[The Ghost]

re the above I mean above Pat H and Buzzlightyear

help out a friend with no money

 

[buzzlightyear]

try salvation army.

 

[Tony Good]

I've made sure the current is off before going near anything and may well post a picture of the wall switch tomorrow. Looking at some typical lighting circuit diagrams I can see how it should be wired up but can't find anything that shows the way the switch is currently wired and can only suppose it is wrong. Will find an electrician tomorrow who can hopefully help. Thanks anyway guys.

 

[Tony Good]

If you only altered the wiring in that ceiling rose then yes you have interrupted the normal L/N feed that loops from one fitting to the next. All the lights normally have live and neutral and earth fed to them from the consumer unit. Most ceiling fitting have a bus bar at one end connected to the neutral of the light flex this bus bar has the incoming Neutral and outgoing neutral (unless its the last light in the chain)
The bus bar on the other end connects to the live light flex via the switched live feed.
The center bus bar has the incoming live and outgoing live (unless its the last light in the chain) and then it also has the live feed to the switch. The complication is the cable used to go the switch is normally a twin and earth so has a live neutral and earth wire and it actually switches live so we have to indicate that the neutral is actually carrying live and we do that by putting a sleeve on each end to match the live colour.
But often that sleeve isn't present so its easy to get wires mixed up.
What's needed is to identify the incoming feed the outgoing feed and the switch wire.
Easy if you know what's what but dangerous if you don't.
Its not a big job for an electrician and I'd advise you get some help to be sure its correct and safe.

Very helpful post, thank you. Two of the wires behind the switch do have sleeves on but the ones in the ceiling do not.

 

[Pat H]

Is the switch with the sleeved wires one of a pair? Is there a matching switch somewhere?

 

[buzzlightyear]

frank spencer comes to mind !

 

[Tony Good]

Pat, tricky to describe but there basically two switches on the plate. The twin and earths that come from each ceiling light to the back of the switch are interconnected between the switches, which just seems wrong.

 

[Pat H]

So each light only has one switch that operates it but both those switches are on the same switch plate.
If that's the case there shouldn't need to be any connection between switches. BUT its possible the live from the first light is being bridged across into the second switch to then be switched to the second light.
That avoids a live feed needing to come from the second light. But that's not normal as you need a wire to feed the switched live to the second light so you may as well send the live down one core of that wire and the switch live down the other. You'd need to look at the second lights fitting to see the bigger picture.

 

[Tony Good]

Pat, yes both switches on same plate but to my mind, and as you've suggested, they should be seperate, but they are not. One sleeved wire goes into each common terminal on each switch but the L1 connected wires are swapped between the two cables, which just doesn't make sense.
Going back to your original post, I'd need to ascertain the live feed and the output feed in the ceiling fixtures (both have the same amount of wires so I assume this isn't the end of the chain) then go from there... or call an electrician. Thanks for your help anyway Pat.

 

[buzzlightyear]

it would have not been a problem if it was looped from a switch,then looped from a centre light .

 

[Tony Good]

Thanks buzz, too tired to think about it now - gnight all

 

[Pat H]

That wiring does sound odd. But there is no way to end up with the lights in series (as must be happening to have them glow dim) unless one of the lights isn't connected probably to neutral. if both lights have one side connected to neutral then they work or they don't (or it goes bang) so my guess is the feed to the second light is wrong.

 

[Tony Good]

Pat, thanks for your input, I think you are right that the feed to the second light is wrong somehow. I also think the switch wiring is wrong. With a clear head tomorrow morning I'll re-read all of your posts, have one last look (with the juice off) and if no joy then I'll call a spark. Thanks again for your most intelligent responses.

 

[Nickj]

Tony, feel free to post a picture of the switch wiring tomorrow. If it's a simple fix I'm sure someone will point it out.

Take serious care when investigating

 

[Tony Good]

Tony, feel free to post a picture of the switch wiring tomorrow. If it's a simple fix I'm sure someone will point it out.

Take serious care when investigating

Will do, cheers Nick

 

[sparksburnout]

and if no joy then I'll call a spark.

God help the poor B^^^^^d!!!

 

[Tony Good]

God help the poor B^^^^^d!!!

I don't believe in god but thanks for the sentiment. My father is alive and well.

 

[sparksburnout]

I don't believe in god but thanks for the sentiment. My father is alive and well.

I don't either, it was just a figure of speech. Funny how a lot of statements of exasperation can centre on religion! Oh for Christs sake!, Jesus!, For Gods sake....and so on. In fact it is sometimes hard to find one off the cuff that is not so inclined. Can you let us know what the unfortunate Electrician that gets that call uses for an utterance when the above is re-iterated to him upon his arrival?

 

[Tony Good]

I don't either, it was just a figure of speech. Funny how a lot of statements of exasperation can centre on religion! Oh for Christs sake!, Jesus!, For Gods sake....and so on. In fact it is sometimes hard to find one off the cuff that is not so inclined. Can you let us know what the unfortunate Electrician that gets that call uses for an utterance when the above is re-iterated to him upon his arrival?

Will do, hoping to return good news about nine wires...
Honestly, I'm humbled. As a software developer I'm used to dealing with complexity but this has me stumped, if I can get someone in who can say "I know!" my hat's off to them.

 

[Midwest]

Lights glowing when they are off, as has just been said by Snowhead!, indicates that the light is getting a supply from the neutral of another light so both lights in series gives a dim glow as they are at half voltage.

Wot these two chaps said. Don't start taking switches off and making the problem worse. You've just messed up the connections in the light, unless the person who put the light up originally did!
Employ an electrician, who will terminate the cables slightly better anyway.

 

[DPG]

I'm sure 'bigsparks' is actually Davesparks in disguise. The forum seems to be going the way it went ages ago, ie. downhill. Oh dear. Daz

 

[Darkwood]

Can we get back on track guys, I've deleted several posts relating to poor and dangerous advice given by a member, a PM will be sent regarding the post, can I please ask you again to report such posts as oppose to pulling the thread off topic and or lowering the tone with personal attacks on other members.