Only half a lighting circuit is working

[pm50]

I have a peculiar fault which I would appreciate some help with. One half of one of my lighting circuits is not working. The circuit is working in 3 rooms, but not working in 3 others or on the landing. The top landing and rooms are all part of a loft extension done many years ago and all have low voltage downlights. The downlights in the rooms are controlled using dimmer switches. None of these downlights are working. In addition, a light in the study below the loft extension does not work (conventional halogen bulb) and 2 other conventional landing lights do not work.

Apart from the odd bulb and transformer, nothing has changed for years.

Any ideas?

 

[EFLImpudence]

If all the lights are on the same fuse or circuit breaker then I would assume that you have a loose wire - somewhere.

Likely at the last light that works or between that light and the next on the circuit.

Starting at the consumer unit you may be able to roughly tell in what order the rooms are connected.

I would not think it anything to do with the types of light.


Incidentally, 240V is low voltage; 12V is extra-low voltage.
Few manufacturers or shops seem to know.

 

[PrenticeBoyofDerry]

I think the first question is has anyone worked on the circuit prior to this circuit failure or has any other work been undertaken that could have disturbed or damaged it?

If you have extra low voltage lamps do these work of one transformer or each lamp individually?

Most likely event is that you have either or both a neutral or live disconnected, loose, damaged. This would now need further investigation, and looking at each fitting and switch for loose/damaged connections. The fault is likely to be at the first light/switch that is off or the last one that is on, that is if you are aware of how your circuit is run.

 

[pm50]

Unfortunately I do not know which way the circuit runs or even if it is a ring. Are lighting circuits normally rings? I am wondering whether there was a ring, but the extension lights were just from a spur.

Could a blown transformer be causing this? I have had them go in the past and they just seem to affect only a single light. The connections in the switches all appear fine, so I guess it is just a case of checking other connections?

The downlights are 12V by the way, mostly halogen with a few LEDs.

 

[EFLImpudence]

Are lighting circuits normally rings?

No, just a radial (line)

Could a blown transformer be causing this?

Not all of them.

 

[pm50]

Thanks, then I guess the hard work begins!

I just hope I can get to all the connections easily.

 

[pm50]

I fixed this by the way. Last ceiling rose I checked before looking into the inaccessible downlight wiring. There was a loose connection in a chandelier I put up myself about 15 years ago!

Thanks again for the assistance.

 

[EFLImpudence]

Ah, very good.

It's always the last one.

Thanks for letting us know.