Lighting Problem

[johninlondon1]

Any ideas would be appreciated in solving the problem.

Removed completely bathroom ceiling as it was completely ruined, had light and pull cord hanging until replaced ceiling and completed plastering.

On completion, re-fixed both of them and switched off upstairs mcb but downstairs mcb tripped as soon as I turned off upstairs lighting circuit. Reconnected light and noticed switched live had come out of terminal block.

Re-connected and on turning lights on for upstairs all is ok but still downstairs will not work. I have not touched any downstairs lights or switches.

A new consumer unit was installed in November 2011 and all lighting upstairs circuit has old wiring in bad condition and 3 terminal blocks used for connection of new bathroom light.

The cables look worn and signs of blackened outer sheath and was surprised that no re-wire was done at same time of ccu change. I have checked in the loft to ensure cables not damaged due to me screwing new plasterboard and no sign of damage. Re-checked all connections to upstairs lighting circuit and all appear to be ok.

Thought maybe a borrowed neutral from downstairs circuit or possibly water ingress from plastering but never spilt any so this would be unlikely.

Any ideas as I am still in study and not much experience on fault finding and don't want to make things worse?

Thinking I am going to have to shell out for an electrician and there goes most of the plastering money I earned. It's a friend and done plastering at mates rate.

 

[NozSpark]

This is a job that you have done?

What you should have done is pushed the fittings and switch into the loft and then get an electrician in to refit them properly:|

You do not need to have spilt water for it to have caused a problem, as you know wet plaster contains water.

 

[Doc Hudson]

MCB tripped, or RCD tripped? MCB would be a dead short somewhere, if definitely MCB have you got a black switched live from a downstairs circuit that you have now connected onto a neutral?

Doc H.

 

[johninlondon1]

Definately MCB tripped, RCD was un-affected. There are 2 x 6a mcb's in CCU - one stating ground floor light and other is 1st floor light.

 

[lineman]

Just to confirm that the switch live is definitely correctly identified? Is it loop in at the switch or at the light? What caused the ceiling to be ruined? Just chucking some ideas out there

 

[ProDave]

That was a long post with no punctuation so hard to read.

Have I got this right:

You have re connected the UPSTAIRS bathroom light after the ceiling was replaced, and that light now WORKS as do ALL of the upstairs lights?

The DOWNSTAIRS lighting MCB now trips, so no downstairs lights work at all?

But you have not done any alterations to the downstairs light circuit?

Is that a correct summary?

 

[johninlondon1]

Thank you Pro Dave. What you have written is an accurate summary. The upstairs lighting is all working but the mcb for the downstairs lighting is not working, it is in the off position and when mcb switch is pushed up it doesn't click into place, just stays off.

 

[ProDave]

Is it one of those MCB's that when it trip's it ends up "half way"

So before you can reset it, you have to first press it down, it will go click, then you can press it up and it will turn on.

 

[edeg24]

Is it a split load board?

 

[lineman]

Is the mcb knackered? Does it feel floppy?

 

[kme]

Is it one of those MCB's that when it trip's it ends up "half way"So before you can reset it, you have to first press it down, it will go click, then you can press it up and it will turn on.

Mk iirc; they denote a tripped condition, to differentiate from a switched off condition. If it isn`t this type, query MCB fubar?

The other question that arises: WHY did the downstairs MCB trip out in the first place? Does it have a connection to the upstairs, electrically?

 

[Mr T]

Maybe a borrowed Neutral between the 2 way stairs/landing scenario ??

Are the neutrals connected in the right order i.e. MCB next to the main switch would be circuit 1 so Neutral would go in neutral number 1 same applys for the CPC..

Does the board have 2 RCDS and are each lighting circuit on seperate RCDS ? If so Check the Neutrals and where they are connected ?

Does the board have 1 RCD and is the lighting on the RCD side or the non RCD side ??

Just throwing a few questions out there ? However you say the RCD doesnt trip so that wouldnt suggest a Live or Neutral to earth fault ... Can you post a picture of the consumer unit and point out which is the lighting circuits (in case its not marked up)

 

[sparkytim]

Sounds like your "Floppy" MCB has had it. Not a 6A Hagar by any chance?