downstairs lights not working

[xulochavez]

Hi, a very basic problem: the lights downstairs aren't working. I guess there are two possible answers:

1. A short circuit somewhere. I think this one is not possible because I have switched the MCB on and it stays on

2. An open circuit (happened to me before). I think it's not very likely on the lights themselves, as I havent touched them for months. It's true that I installed two of the ceiling lamps and didn't do the best of jobs, so wires could become lose. I checked these two and it didn't seem to be the case

My best guess of the cause is the heating. The lights went off around 19:00, which could be the time the heating went on. It's possible that the heating (of which I know precious little) is connected at the very beginning of the lighting circuit (since it's installed in a small room next to the living room). Is it possible that something caused the circuit to become open just after the heating (since the heating is working)? I guess there can't be a short circuit, as the MCB would jump as soon as I tried to switch it on

Sorry for the basic question, I just want to get a clue before I call an electrician, thanks!

 

[Taylortwocities]

Your heating should not be on the lighting circuit!

Almost impossible to say without being there. Could be a number of issues and some will depend on how the house lighting circuit is wired. It needs someone with a multimeter and some expertise to check.
If its all of the lights then the fauult will be near the beginning of the circuit.

Start at the consumer unit using a test meter:
Check the MCB, the switch may be on but are there volts coming out of it (they can fail)?
Then its looking at light fittings and switches to find out where the run is. Is your lighting done by the 'loop in' method or is there a big multi-connection box buried under the floorboards?
Double check your previous work. Sometimes conductors can snap off inside the insulation if they have been mistreated in the past.
etc etc etc

I'll bet you'll need to get a spark in..

 

[Spark123]

I don't like the sound of your MCB jumping when you tried to turn it on! Sounds like there may be a fault still on the system.
Best ask friends or a neighbour for names of a reputable electrician.

 

[Taylortwocities]

I dont think thats what he meant, Spark.
I think he means that if there was a short then the brreaker would jump, but he told us the breaker stays on......

Where's me Bombay Sapphire & Tonic??




Aah that's better

 

[Deleted member 54734]

Not been drilling any holes in the wall lately have you?

This happened to my mate when he moved in to his new house.
He was fitting a new kitchen (cooker etc) so luckily he still had the electric off when he put his coat rack up above the CU.

Putting his coat rack up he managed to drill through his downstairs lights so when he turned the CU back on their was a bang and he couldn't work out why his upstairs lights worked when the downstairs didn't as they were on the same MCB.

 

[xulochavez]

Thanks for the replies guys. The problem affects all the lights downstairs, so as you say it has to be at the beginning of the circuit (the circuit is done by the loop-in method).

Also I think the MCB is ok because as I switch it on and off there is a control for the heating that switches on and off (the heating is communal, so it's not on the same circuit, but some local control is most likely on this circuit, as the heating was installed after the original electric installation, and (some part of) it is installed next to the living room)

So an open circuit at the heating (controls) is a good candidate, I was a bit doubtful because I thought that it was normally short circuits that happened spontaneously, but then I guess wires can snap / connections can get loose by themselves

I'm pretty resigned to get the electrician in (im a newbie at electric diy), but before that I'll get a multimeter and try to get some measurements. What would be the typical measurements you'd take to detect the open circuit (I imagine you're looking for infinite resistance between two points)?

 

[ban-all-sheds]

Where's me Bombay Sapphire & Tonic??

Fever-Tree I hope...

 

[Taylortwocities]

I usually save the Fever Tree to go with the Martin Millers!
http://www.millersgin.com/

 

[xulochavez]

In the end I got an electrician, a guy that works for a guy that works for my flatmate, so he didn't charge me but then I'm not sure how good he is. He noted that the circuit was dead, tested each of the lights and said that there must be a broken wire somewhere but can't tell where.

He fixed the lights by using a double switch downstairs wich controls both the lights upstairs and downstairs corridors, I guess connecting the live that was comming from upstairs to the one downstairs, and so getting all the lights on the same circuit.

He said I should get the whole flat rewired, and I agree since the installation is the original one from the 70s and looks completely knackered, plus I haven't got any schemes of the wiring so I'm completely blind if anything goes wrong like now. But I was disappointed that he couldn't work out where the fault was, so I'm not so sure I'd like to trust him with the re-wiring

 

[Taylortwocities]

Before you use anybody, check they are a registered spark. They should be listed here: www.competentperson.co.uk

If they are on this list then generally they are a registered spark who is part of one of the schemes that allow electricians to notify their own works.
The schemes have membership requirements that mean the electrician should have a level of competence and they will be checked on an annual basis.

Its never an absolute guarantee but a good start.
Better, get a recommendation and then check they are on the list!

 

[xulochavez]

Thanks for the tip TTC.

By the way do you reckon it's a good idea to completely replace a 70s wiring in the flat? I worry that it may be overkill, but then the current installation does look destroyed. My main hope is that once I get it rewired I'll have a decent schema of what goes where and it will be easy to find and fix faults like this. If that's something achievable then I think it would be worthwhile.

 

[ban-all-sheds]

I usually save the Fever Tree to go with the Martin Millers!

I'll have to give it a try.

But cheap tonic is a mistake in any G&T - there's more of it than the gin....

 

[Taylortwocities]

Have your existing wiring checked by someone who is competent in inspection & testing. Ask for a Periodic Insopection Report.

this will detail anything that must be done and will say what wiring etc is fit for purpose.

It will ciost you a couple of hundred but will say what really needs to be done. Its a good idea to use a different spark to do the remedial work to the one who does the report.
That means the inspection man doesnt make work for himself !!!

 

[xulochavez]

I was thinking again and realised that:

1. I know that the heating timer is at the beginning of the problem circuit, because it works while none of the lights work (and stops working if I switch the MCB off). Now I have additional proof, because as I source the live from the upstairs circuit (and have the problem circuit off), all the lights work but not the heating timer.

2. I know the first light in the problem circuit is the one in the living room (which is where the heating timer is), because when I installed a lamp there and forgot to connect one wire none of the lights worked

So, the fault must be between the timer and the living room light. Surely an electrician should be able to confirm this and replace any wire that was necessary

In any case I'll ask for a proffesional inspection of the whole flat, that might be enough rather than the full rewiring

 

[ban-all-sheds]

Have you opened up the heating controls to see if you can spot anything wrong?