# Is there a electrician in the house?



## swee'pea99 (23 Sep 2022)

Taking as read that I should get someone in who knows what the hell they're doing and stop being a bloody idiot, I find myself proper baffled, and wondered if the CC posse might have thoughts on the matter.

To whit:

I took the light fitting down from the hall when we were having the place replastered, and now I've put it back it doesn't work. And - and here's the funny bit - nor does anything else.

I know how the light fitting connects - I put it up in the first place - but took the precaution of taking a photo before removing it:







When I'd finished everything else in the hall I just put it back as it had been, and switched on, and... nothing. Subsequent ponderings and fiddlings have brought me to what seems a very weird situation, which is that if I test the contacts the brown and blue wires would be using - the extreme outside ones - using an electrical screwdriver, the wee neon lights up orange for both. But if you connect the lamp fitting - or any other electrical device - to those contacts, it doesn't work. I've tested it using my desk lamp, which works perfectly. Nope. 

How can this be? And what should I try next (apart from the obvious)?

It occurs to me it might be worth a mention that tho' the neon light does come on, without question, it's not exactly burning bright...mean anything?

Thanks for any feedback. Feel free to go for the obvious. Fill yer boots. Don't thank me, it's what I do.


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## fossyant (23 Sep 2022)

Have you connected the ring main properly. Those there will, or should be three separate circuits, but you should have wires going to the outer two connectors as well.


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## si_c (23 Sep 2022)

swee'pea99 said:


> Taking as read that I should get someone in who knows what the hell they're doing and stop being a bloody idiot, I find myself proper baffled, and wondered if the CC posse might have thoughts on the matter.
> 
> To whit:
> 
> ...



Firstly, I'm not an electrician, but I have done a fair bit of DIY stuff with electrics. It's worth pointing out that you're using a voltage sensor which can detect flow if you have an open neutral, this is where you have lots of circuits with a common neutral running back to the board, this is likely to be the case with a lighting circuit.

My first thought is that you've not connected up the wiring properly, I'm assuming that it is a single light fitting with a single switch, so you might have two or three wires coming together at the pendant backplate plus the line out to the lamp itself.

If you have only two wires behind the lamp then you have just the switch and line in, if you have three then you have a ring setup where there is a feed to the next light in the ring as well.

Either way this picture should help undersand how the wiring should look. Click on it for a better explanation


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## presta (23 Sep 2022)

Unless the rose is the last one on the end of the circuit, it will have an output to the next rose:


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## cyberknight (23 Sep 2022)

assuming you wired it up right it could be when you put it all back up some wires have touched inside and you have shorted out your fuse /trip box


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## swee'pea99 (23 Sep 2022)

Thanks very much!

My circuit looks like the one Presta posted - a bunch of wires in the middle, none of which I've ever touched - with the light fitting wires going into the outermost holes on each end.






Am I understanding this right - when you say


si_c said:


> you're using a voltage sensor which can detect flow if you have an open neutral,


...does that mean that my dim-glowing electrical screwdriver might just be registering 'flow from my open neutral', which is why it won't power my desklamp? That although it 'looks live', there's not actually a working voltage/amperage/whatever at those contacts?

One thought that occurred to me while I was doing backstroke earlier...a few weeks ago I discovered the living room light wouldn't come on. At the time I just added it mentally to the list of Things I Have To Do (but no real urgency). But might there be a connection? Is this time to check the fusebox? (The 'Downstairs lighting' switch in the box seems fine - doesn't refuse to go on or anything.)

Thanks again for all posts, really appreciate the help.


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## si_c (23 Sep 2022)

presta said:


> Unless the rose is the last one on the end of the circuit, it will have an output to the next rose:


That looks right to me. And from what the OP posted seems to corroborate that. I have a slightly different setup on some (but not all) of the lights in my house, they are older pendant style lamps with no wiring plate in the base so the wiring is done in the ceiling using wiring blocks, it's ugly but functional and I could rewire them all but I'm not going to bother doing that until I replace all the light fittings.



swee'pea99 said:


> Am I understanding this right - when you say
> 
> ...does that mean that my dim-glowing electrical screwdriver might just be registering 'flow from my open neutral', which is why it won't power my desklamp? That although it 'looks live', there's not actually a working voltage/amperage/whatever at those contacts?


That's my understanding, yes. If you think about the wiring diagram above, all the neutral lines in a lighting circuit run together at some point (the consumer unit if not sooner), in simplistic terms the live wire carries the current to the light and the neutral carries it away, the reason it can do this is it should sit at 0V where the live wire sits at 220V. It's this difference between the two that allows the current to flow back to the power station.

In practice however the balancing that is done to let this happen may not be perfect, so you can get some potential voltage bleeding through in your home system if that is the case, it is always low as the voltage on the neutral should be 0V, but if the voltage is say 0.1V depending on the sensitivity of your voltage detector it may pick that up.

Edit to add: Regardless of how low the voltage on the neutral line it is always a bad idea to work on electrical systems live. Always turn the circuit off first and verify.


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## Phaeton (24 Sep 2022)

Start with the usual, not a Sparky, but done all my own stuff for years, 

Looking at your photo the 2 blacks on the left are your negative line circuit, I'll call them line as they are not a ring. The 3x reds, 2 again are your line & the 3rd goes down to your switch, the circuit comes back from the switch on the black with red tape on it, it has red tape on it because when the switch is closed that wire has live on it. Logically your bulb needs to go between the outside set of connectors black & black with red tape.

Things to check, do you have a good bulb? because it worked when you took it down doesn't mean it will now, has the switch plate been off, have you checked the wiring in the back of there? If you connected your bulb wires between the 3 reds & the 2 blacks is it constantly on? Do any of you other lights work?


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## CXRAndy (24 Sep 2022)

Don't use neon test lights. They give false live readings if neutral is floating. A proper digital multimeter is best. If you know how to use them 

Brother in-law used a neon to fault find a faulty electric lawnmower. Having fitted new switch, brushes. He phoned me .

Two minutes later found fault broken neutral wire before switch


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## swee'pea99 (24 Sep 2022)

Thanks again!



Phaeton said:


> Things to check, do you have a good bulb? because it worked when you took it down doesn't mean it will now, has the switch plate been off, have you checked the wiring in the back of there? If you connected your bulb wires between the 3 reds & the 2 blacks is it constantly on? Do any of you other lights work?



The bulb's fine (and I've also checked with my desk lamp, which also works fine). Has the switch plate been off? Yes it has! I should have thought of that. The plasterers loosened it off. That's definitely one to check. "If you connected your bulb wires between the 3 reds & the 2 blacks is it constantly on?" No - it's constantly off. Nothing I've connected to that ceiling fitting seems to work, regardless of whether it's switched on or off.

Would I be right in thinking that since the switch stays happily in the 'on' position...






...this can't be a universal 'ground floor lights' issue, but must be localised to this one ceiling fitting? (With some problems in the past, the switch simply wouldn't stay 'on', but insisted on flipping back down until the problem had been dealt with.)

PS I've suddenly noticed, since posting this pic, the wee black bit in the middle of that - and only that - switch.






Does that mean anything? And if so, where should I start in looking for a solution?

Thanks again! Feel like I might be getting somewhere! Two steps forward, one step back...


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## Phaeton (24 Sep 2022)

If you also say that the living room light does not come on, if the feed comes from the CU (consumer unit) to the living room, then to the hall the fault may not be in the hallway connections. Do any other lights on the ground floor work? If they do, do they stop working when you turn off that breaker?


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## swee'pea99 (24 Sep 2022)

Phaeton said:


> If you also say that the living room light does not come on, if the feed comes from the CU (consumer unit) to the living room, then to the hall the fault may not be in the hallway connections. Do any other lights on the ground floor work? If they do, do they stop working when you turn off that breaker?



The 'LIGHTS GROUND FLOOR' switch only connects to the hall light and the living room. The other ground floor lights are all on LIGHTS KITCHEN.

That black blip is calling out to me.....I just don't know what it's saying...

Once I've finished this coffee I'm going to take a look behind the switch in the hall - the one the plasterers removed.

Talk about a cliffhanger...


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## Arrowfoot (24 Sep 2022)

I had garage lightbulb that stopped working all of a sudden. So much time spent on DIY trouble shooting. Finally called sparky who recently passed his apprenticeship. Used to follow his boss on work assignments. Traced the fault to a an upstairs bulb fitting in one of the bedrooms in 10 minutes flat. Till today I have no clue what happened. And I will remain clueless.


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## swee'pea99 (24 Sep 2022)

Disappointingly it all looks rather in order...






Hmmm.... <strokes beard thoughtfully emoji>


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## Phaeton (24 Sep 2022)

Please think about what I'm putting BEFORE you attempt it & be VERY happy doing it BEFORE doing it.

Switch off the power at the main CU, remove the cover of the CU, then next to the fuse you are working on is a spare 6A one, WITH THE POWER OFF unscrew the live & swap it over to the spare then put the power on & see if your lights work.

If you're not happy to do this then a Sparky is you next logical step.


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## Phaeton (24 Sep 2022)

Just another thought, you say this is the hall light, is it also the landing light, there looks to be too many wires in that image behind the switch


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## midlife (24 Sep 2022)

That black dot on the mcb would make me wonder what's different to the others. Not an electrician but would be curious


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## si_c (24 Sep 2022)

Phaeton said:


> Just another thought, you say this is the hall light, is it also the landing light, there looks to be too many wires in that image behind the switch



That was my thought, for a single switch there should be a Live (Red/Brown) going into the slot labelled COM and the sleeved Red/Brown going to the L1. Having a line to the L2 indicates that this is a dual position circuit.

Looking at the my first thought is it's wired incorrectly. You should have EITHER a single wire going to each slot OR two each in L1 and L2 and a single in COM.

In the first case the Live should be going to COM on one switch and the Switched Live (Sleeved Live) should be going to the COM on the other switch. In the second case you will have the same cable going to COM on each switch and one LIVE and one Switched Live running to the L1/L2 on one switch and a separate pair of wires joining the L1/L2 circuit.

Neither appears to be the case here, you have two live cables running to the L1 and separate L2/COM single wires (I'm assuming the L1/L2 orientation here I can't read from the switch).

At this point I'd be getting my continuity tester out and checking what actually runs where.


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## Phaeton (24 Sep 2022)

This is how I think it should be wired, I believe this is a 2-way circuit with either another light upstairs or at the very least another switch at the other end of the hall. Your ceiling rose has the Live & Neutral coming in, it also has a Live & neutral going out to the next lighting rose. It then has a 2 core & earth going down to the switch, with a 3 core & earth going to the next switch. ut it still comes back to the fact your bulb should be across the black & the black with red tape. Earth not included in drawing


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## si_c (24 Sep 2022)

Phaeton said:


> This is how I think it should be wired, I believe this is a 2-way circuit with either another light upstairs or at the very least another switch at the other end of the hall. Your ceiling rose has the Live & Neutral coming in, it also has a Live & neutral going out to the next lighting rose. It then has a 2 core & earth going down to the switch, with a 3 core & earth going to the next switch. ut it still comes back to the fact your bulb should be across the black & the black with red tape. Earth not included in drawing
> 
> View attachment 662184



Took me a moment to understand your switch orientation, but yeah that's about right.


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## newts (24 Sep 2022)

Have you tried switching the ground floor lights mcb off then back to see if it resets?


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## classic33 (25 Sep 2022)

swee'pea99 said:


> Thanks again!
> 
> 
> 
> ...


It's in need of replacement
https://www.electriciansforums.net/threads/lighting-mcb-keeps-tripping.170714/post-1488918

Looking further it seems to be a known problem/issue with MK MCB's. Not very good.


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## swee'pea99 (25 Sep 2022)

Once again, many thanks everyone - this is really helpful. Ok...



newts said:


> Have you tried switching the ground floor lights mcb off then back to see if it resets?


Yes, but it makes no odds. Thing is, if it had tripped, I'd understand it. (That's happened before, and meant I had to sort out a problem before the switch would stay in the 'on' position.) But it's on/untripped. 



Phaeton said:


> Just another thought, you say this is the hall light, is it also the landing light, there looks to be too many wires in that image behind the switch


It's just the hall light, but it is connected to two switches - you can turn it on/off using 'its own' switch, or the (double) one on the first floor landing. 

Beyond that, the wiring diagrams and the like are over my head, but the essentials are, I've done nothing to anything in that ceiling fitting other than to remove a lamp from those two outermost contacts and put it back. All the other wiring is untouched, and exactly as it has been, working perfectly, for upwards of 20 years.



Phaeton said:


> Please think about what I'm putting BEFORE you attempt it & be VERY happy doing it BEFORE doing it.
> 
> Switch off the power at the main CU, remove the cover of the CU, then next to the fuse you are working on is a spare 6A one, WITH THE POWER OFF unscrew the live & swap it over to the spare then put the power on & see if your lights work.
> 
> If you're not happy to do this then a Sparky is you next logical step.


Now this sounds very intriguing! Makes sense. So basically I'm abandoning the (black dot) circuit for the one next to it - currently labelled 'SPARE'. And if I understand you right, that means turning off the Big Red Switch, then removing the casing, presumably starting with the screws in the red circles....





...at which point it will be immediately obvious how to switch the ground floor lights from 'LIGHTS GROUND FLOOR' to 'SPARE' - with relabelling obviously, assuming it works. 

Is that right?

Thanks again.


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## newts (25 Sep 2022)

I would strongly advise not to remove the cover on the main board, this is very dangerous & potentially lethal. I would call in an electrician who will check the wiring to the ceiling rose & the mcb.


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## Phaeton (25 Sep 2022)

swee'pea99 said:


> Once again, many thanks everyone - this is really helpful. Ok...
> 
> 
> Yes, but it makes no odds. Thing is, if it had tripped, I'd understand it. (That's happened before, and meant I had to sort out a problem before the switch would stay in the 'on' position.) But it's on/untripped.
> ...


Yes, that is correct, but be aware that even when you have switched off the Red switch there is still a LIVE WIRE in there, if you follow it from your meter it will come to the top of the switch.

As above if you are not confident DO NOT DO this, but once inside you can simple undo the screw holding the wire into the 'black' MCB & then put the wire into the Spare MCB


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## classic33 (25 Sep 2022)

swee'pea99 said:


> Once again, many thanks everyone - this is really helpful. Ok...
> 
> 
> Yes, but it makes no odds. Thing is, if it had tripped, I'd understand it. (That's happened before, and meant I had to sort out a problem before the switch would stay in the 'on' position.) But it's on/untripped.
> ...


What caused the MCB to fail though, and is there any guarantee that the one you switch to won't fail in a similar way?


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## swee'pea99 (26 Sep 2022)

Phaeton said:


> Yes, that is correct, but be aware that even when you have switched off the Red switch there is still a LIVE WIRE in there, if you follow it from your meter it will come to the top of the switch.
> 
> As above if you are not confident DO NOT DO this, but once inside you can simple undo the screw holding the wire into the 'black' MCB & then put the wire into the Spare MCB



Thanks. Wish me luck, I'm going in... 



classic33 said:


> What caused the MCB to fail though, and is there any guarantee that the one you switch to won't fail in a similar way?



Don't know, none at all. Either way though, I'll learn something, and that has to be a move in the right direction, right?

Thanks again.


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## fossyant (26 Sep 2022)

Are you still with us. Boom !


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## classic33 (26 Sep 2022)

fossyant said:


> Are you still with us. Boom !


No reply yet!


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## Phaeton (26 Sep 2022)

Now I'm worried


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## si_c (26 Sep 2022)

Phaeton said:


> Now I'm worried



He's turned the leccy off, it's all gone horribly wrong and he's now waiting for an emergency sparky.


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## Phaeton (26 Sep 2022)

si_c said:


> He's turned the leccy off, it's all gone horribly wrong and he's now waiting for an emergency sparky.


As long as it's not


si_c said:


> He's turned the leccy off, it's all gone horribly wrong and his wife is now waiting for the emergency services


Or even worse still


si_c said:


> He's turned the leccy off, it's all gone horribly wrong and his wife is now waiting for the emergency undertaker


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## Phaeton (26 Sep 2022)

4 hours, tick, tick, tick


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## classic33 (26 Sep 2022)

Phaeton said:


> 4 hours, tick, tick, tick


Nearer five hours.

Clock stopped ticking when the electric went. 
Hope he's okay in all seriousness


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## newts (26 Sep 2022)




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## swee'pea99 (26 Sep 2022)

Sorry folks, didn't mean to worry anyone! I've put it off till tomorrow, for one reason or another. Still plenty of time to get your 'With Sympathies' cards


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## Phaeton (26 Sep 2022)

newts said:


> View attachment 662462



I'm glad it didn't say Rest in Pieces


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## swee'pea99 (27 Sep 2022)

Just in case...today's out too. I will post in the aftermath, promise.


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## si_c (27 Sep 2022)

swee'pea99 said:


> Just in case...today's out too. I will post in the aftermath, promise.



Sounds like procrastination to me


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## swee'pea99 (28 Sep 2022)

si_c said:


> Sounds like procrastination to me



Never rule out blind terror... 

Ok, good news first: I'm alive & kicking.  Bad news next: failure .

Switched the wire over, as per instructions, same difference: living room light won't come on (and I've tested/swapped bulbs, so I know it's not a bulb issue), and the hall contacts seem as dead as before: the testing screwdriver glows on the red contacts, nothing on the black. And my desk lamp wired to the appropriate contacts is dead as a doornail. Much as it goes against the grain I think it might be time to call in The Man. Unless anyone has any other ideas I could try?


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## si_c (28 Sep 2022)

swee'pea99 said:


> Never rule out blind terror...
> 
> Ok, good news first: I'm alive & kicking.  Bad news next: failure .
> 
> Switched the wire over, as per instructions, same difference: living room light won't come on (and I've tested/swapped bulbs, so I know it's not a bulb issue), and the hall contacts seem as dead as before: the testing screwdriver glows on the red contacts, nothing on the black. And my desk lamp wired to the appropriate contacts is dead as a doornail. Much as it goes against the grain I think it might be time to call in The Man. Unless anyone has any other ideas I could try?



I'd have called in the Man before now to be honest.


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## Phaeton (28 Sep 2022)

Okay at least you learnt something new & lived to tell the tale, have you put the wiring back in the CU as it was before? If not you may have introduced a 2nd fault which The Man may have to figure out as well.


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## fossyant (28 Sep 2022)

Get "The Man" before you have your own mini Nord Gas Pipeline explosion


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## newts (28 Sep 2022)

Is the neutral from the lamp fitting into the ring/loop missing?


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## Phaeton (28 Sep 2022)

newts said:


> Is the neutral from the lamp fitting into the ring/loop missing?



I suspect the lounge/living room will come into play & the hall is a red herring


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## classic33 (28 Sep 2022)

Phaeton said:


> I suspect the lounge/living room will come into play & the hall is a red herring


Sounding fishy.


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## Phaeton (28 Sep 2022)

classic33 said:


> Sounding fishy.



Batter than it smelling fishy


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## CXRAndy (28 Sep 2022)

It's clear the OP has no practical knowledge of electrical circuits, testing or the basic equipment to do fault finding. 

Pay an electrician to sort it out. 

Even I know when to call in the professionals. I'm very competent with electric/electronics being my trade for 20years. I wanted to swapped out old MCB breakers for RCBOs . I told the wife it would be several hours work, due to awkward consumer unit location. She was having none of it. So I decided to pass the work to our electrician -who eventually came to do the job several months later. It took him 4 hours to change over to RCBOs. 

Nice job he did too. It narrowed down a rare intermittent tripping we had for over a year. Dishwasher dripping water onto its mains input connection. 

Also having a newly upgraded consumer unit helped swing a house sale. The new buyer pleased we had upgraded and had a new building regulations certificate.

Call a sparky


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## bikingdad90 (28 Sep 2022)

When you’ve put it all back together… have you put the ring wiring back in the correct terminals and/or are any of the exposed cables touching? Something like this could be causing the issues.

If you flick another switch in the loop does the light come on?


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## MrGrumpy (28 Sep 2022)

swee'pea99 said:


> Taking as read that I should get someone in who knows what the hell they're doing and stop being a bloody idiot, I find myself proper baffled, and wondered if the CC posse might have thoughts on the matter.
> 
> To whit:
> 
> ...



I’d check your neutral is connected up ? To me it could be just that a dodgy neutral ? If that’s dissed your lights won’t work.


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## swee'pea99 (29 Sep 2022)

Oh ye of little faith...







Thanks everyone - very helpful input throughout...I really appreciate your time and effort.

FWIW, in case anyone's interested, it turned out to be a bit of dodgy wire at the point where the leads were emerging from the cable sheath/insulation, with the earth (exposed) & live a bit too close for comfort. A small screwdriver gently pushed in at that point and wiggled to make a proper separation between the two leads and bingo - all is well. And yes, the living room light is working too. It's all good. 

Another triumph for the CC posse! Woop woop!


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## newts (29 Sep 2022)

I think you need to get that checked properly for complete live, neutral & earth continuity. Live touching earth should have tripped the rcd? Loose connections are a fire hazard.


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## classic33 (29 Sep 2022)

newts said:


> I think you need to get that checked properly for complete live, neutral & earth continuity. Live touching earth should have tripped the rcd? Loose connections are a fire hazard.


It was showing as having failed. The black mark, when all the rest were red.


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## newts (29 Sep 2022)

classic33 said:


> It was showing as having failed. The black mark, when all the rest were red.



The rcd is in addition to the mcb, there's 2 rcd's on the op's consumer unit. Anything touching the earth should trip the rcd.


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