Fault

[daiplayer]

ok, following a call out to a house that had attempted to change their own light fitting, and obviously got lost,
Showed up to find three cables sticking out of ceiling, ( immediate thought, perm in, perm out, and switch cable, simple)

Upon testing, cable 1 : 230v in , ( perm in)
cable 2 : dead ( perm out )
cable 3 : dead, belling out in sequence with switch, ( switch cable,)

ok , easy.

However when wired up, light would not switch off !! , thought, ' rookie mistake, got some wires wrong way round, '' checked , nope all correct,

when testing, found that one of the black wires, had 230v - earth, deos not switch off switch, so now ive got : a group of reds ( perm in/outs ( with perm 230v to earht, neutrals : 1 , switch wire, and a random black cable with 230v on it !

Any ideas ?


Oh and the rest of the lights on the circiut are off, ( some on some off )

 

[Specialist]

Maybe a stupid thought but did they only mess with the 1 light ? Had that sort of call before tell you they messed up 1 light but don't admit messing with anymore.

 

[malcolmsanford]

Dodgy switch?

 

[Rappid]

Sounds like a DIY job, DIY'ers don't sleeve live cables, I was thinking on the lines of maybe red and black reverse, one of the red is neutral and black is live.

 

[daiplayer]

I thought exactly the , got a neutral in a live some where, but when i wired it up ( nuetrals common) shouldnt that create a dead short? But it didnt , light just stayed on? Switch works fine, when i removed this 'live neutral' , this light works as should, but no others on the circuit, ????

 

[Rappid]

Maybe the neutral was wired incorrectly from another fitting or used as a switch live

 

[Specialist]

Not trying to teach you your job mate but what did you test it with ? As you said if you put a proper live into the neutrals you should get the breaker tripping. You said it had 230v to Earth what was the voltage to the other neutrals ? Were the lights working before they messed the Fitting up ?

 

[daiplayer]

Not trying to teach you your job mate but what did you test it with ? As you said if you put a proper live into the neutrals you should get the breaker tripping. You said it had 230v to Earth what was the voltage to the other neutrals ? Were the lights working before they messed the Fitting up ?

Not at all mate, teach away,

I got 230v from this odd cable to earth , thats all i know,. and as i said, shouldnt this just trip the breaker when connected ? ...odd thing is , is that when originally i connected this odd l/n in its originally thought place, ( neutral common , the light never switched off when operated, just dimmed slightly,

All the other wires tested as normal

Am baffled,

Just a thought though, saying that this live neutral had been wired into a swl on another light ? what would be the result ?

 

[MarkieSparkie]

1) Check the switch actually switches. What often happens is the customer has miss wired the light fitting with the switch across the supply, bang at switch on! Switch contacts weld in the on position but the rocker still operates. To cover up the mistake they reset the MCB and disconnect all the lighting cables at the fitting.
2)Fault find back along the final circuit you will probably find that a loop-in/loop-out has L-N reversed, where the customer has done another DIY connection.

 

[daiplayer]

the switch and cable appear to be working as should ,

The thing that baffles me is , if they had got the red and black wrong way around in another light, that means that one of the reds ( that is in a connector block common , 3 of) is a neutral, therefore creating a short striaght away , ok im not on site atm , and wont be untill tomo, so cant really do much till then ,

 

[Rappid]

I got a shock once when I was testing on a ring circuit, when I split the ring I got a bolt of one of the wires. It was testing dead before I split the ring, when I retested it, one wire was dead and the other wire had 230V.

 

[topquark]

Have you checked the overall polarity of the supply and the other precursor checks (continuity/IR)?.

Another couple of possibilities: Is the switching single way? (If not then the other end could be wired incorrectly leaving both strappers live). Have they possibly used an intermediate switch instead of a 2way? (Possibly only at one end).

 

[Edd]

When you said about the dimming of the light that sounds like a neutral in series with another light,, wrong swithline /neutral normally means popping of mcb/ fuse or dimming of other lights down circuit,, wonders if customer has screwed around with other lights..

 

[telectrix]

could trhat neutral have 230v on it because the neutral path back to the CU has been lost?

 

[spark 68]

could trhat neutral have 230v on it because the neutral path back to the CU has been lost?​

It could have 230 showing on it if it is being backfed via another lamp, I have come across some strange set ups in my time, such as switches in the Neutral.

Or as others have said, the client has messed around with more than one lamp fitting