light fault

[bono1712]

Right now this one's baffling me so any help would be welcome. My uncle asked me to have a look at his lights in his living room, he's got 2 lights (down lights 4 bulbs on each) 1 at either end of the room and two 2way 2 gang switches again at either side of the room. one of the bulbs blew in 1 light and it tripped the breaker. When he re-set the breaker one light was working and the other one wasn't.

first thing I did was disconnect the light and test the incoming live and neutral and there was 240v so i re-connected the light fitting and then tested again this time nothing, so i disconnected it again and the wires coming through the ceiling had the 240 again.

Like I said the previously the other light was working so just to prove it wasn't the fitting I swapped the fittings over and that never worked either but when I put it back that fitting which previously worked was now not working... YEAH I WAS BAFFLED TOO!!

so basically when the wires coming through the ceiling are disconnected they get there 240v...when connected to the light fitting they lose it, I also tried another seperate lamp a halogen lamp and the same thing the 240v went as soon as it was connected to the load.

The lights have been working for 4 years since his house was re-wired and no new wiring in the switches lights etc has caused this it just happened when a bulb blew.

the fittings also work fine in the hallway where I tested them .

The only thing I can think of and I'm really clutching at straws is there is a loose neutral somewhere on the circuit but it'd need floor boards lifting to check and I was looking for some advice before I started with that... thanks in advance

 

[Spudnik]

If there is only one cable to each fitting, it is possible that there is a junction box under the floor somewhere and that it may be breaking a loose connection when you move the cable?

Just guessing really as it does seem like an odd fault.

 

[bono1712]

thats the only thing i can think of really that there is a loose neutral in the jb and thats bringing the voltage down when a load is supplied to the wires from the jb.

yeah it's only L N & E going to the light chocolate block connecting to the L N & E in the fitting (choc block) so it's impossible to go wrong really, the power is there when not connected to chocolate block when connected to choc block (light fitting) power goes!!... bizzare!!!

the thing is my uncle had his house re-wired 4 years ago and the jb could be under the floor in one of 3 rooms...2 of which wooden flooring has been laid... 5 minute jobs eh? ha,ha

 

[kung]

Agree odd fault afraid only way to sort this one is floor up. good luck !
Regards
Kung
P.S. hello and welcome bono1712

 

[Mr Mark Sparks]

befor you trash the house enlarge hole the cable comes through and see if the 3plate connections are in connectors loose.

 

[Had8Lives]

I'd suggest checking continuity of the circuit at the consumer unit before you get floorboards up.

 

[pete.l]

Could be a dodgy switch!!

 

[ninjadeathstalk]

If the second light worked before, but now will not work while it worked on it's own then it looks like the return from the switch is loose, ie the supply to one fitting disconnected followed by the second fitting.

If you check for a supply at the switch and you find 230V.

Then try a continuity between the switch on the return side to each of the fittings and see if that is ok first. If not then there is a broken/loose connection at the lamp supply terminal on the three-plate connection.

If there isn't 230V at the switch then there is a broken/loose supply to the three-plate connection.

I would have thought it would be at the three-plate connection because it might have been disturbed when changing the fittings over or as stated by jasons6930 before it may be a junction box under the floor if the rest of the circuit is ok.

 

[bono1712]

thanks for the suggestions...I tried both the switches when I was checking the lights so next step is floor boards up...I'm just hoping whoever re-wired the house put the jb in the sensible place under the landing as it's not wooden floor...happy days!!

 

[mrloy99]

thanks for the suggestions...I tried both the switches when I was checking the lights so next step is floor boards up...I'm just hoping whoever re-wired the house put the jb in the sensible place under the landing as it's not wooden floor...happy days!!

sounds to me like your transformers packed in! try sticking a plug top on the end of your fitting before you start ripping floors up just to check fitting is ok or maybe try wireing a pendant drop with lamp(borrow from other room)into your choc box.Let us know.