Lighting circuit problem

5 Sep 2009
Reaction score
United Kingdom
3 light fittings at my sisters house have no Live feed. An attempt to renew a bulb has resulted in breakage of a baked batten bayonet bulb holder and I have gone there to renew it but find that there is no Live on the loop which has 3 red wires. Assuming a blown fuse, I have checked all visible fuses and terminal screws visibly and with continuity test. All are ok, so where can the break in the live be - any suggestions ?

Sponsored Links
3 light fittings at my sisters house have no Live feed.
How long has it been like that?

An attempt to renew a bulb has resulted in breakage of a baked batten bayonet bulb holder
Do you mean it's become damaged through overheating?

where can the break in the live be
Somewhere between the last position which is working and the first one which is not.

Hopefully it's a simple case of a conductor having come loose in that last light/rose (or an idiot breaking continuity when installing a light with only 3 terminals), and not actually a break in a cable somewhere.
Q1: About a week I am told.

Q2: The bayonet holder was damaged when somebody tried to renew the bulb , thinking that was the reason for the light not working.
It was baked and brittle through age.

3: Above the ceiling is an outside flat roof. I have no idea of the cable
routing -
(1) + (3) = bad news, I'm afraid.

Check each light position to see if the loop conductor has come adrift, but if you don't find it then you've got a major job on your hands..... :(
Sponsored Links
How are you testing? I have seen again and again people using neon screwdrivers to test with and as a result the report was completely wrong with neutrals rather than line missing.

The main reason for no power in one lamp is some one has played around with the lamp before it on the radial and thinks telling you what they have done will annoy you so don't tell you.

Being fair it could be as simple as vibration shaking a terminal lose but often not at the failed lamp be one before.
As it is a flat roof, my guess is this is an add - on to the building?

If so, there may be an FCU somewhere that provides power to the lights.
Have a hunt around and see if you can find an unidentified switch/fuse. The fuse may have popped.

PS This is the best prepared question I have seen for quite a while. Is this a question from your college course? ;)
Used multimeter for testing, not neon screwdriver.
The property has a kitchen extension with separate fusebox but the failed lighting is in the old part of the house where a shower room has been installed replacing a pantry or something.
My experience is in electronics, not domestic wiring and having failed to find the cause of problem have advised the householder to get a domestic tooled up electrician on the case. Thanks for replies
College course? I am 74 years of age but still keep up with electronics and computing to maintain my grey matter in good health
You'd be suprised how many questions we get from people who should be learning from their books!

Hope your spark sorts things out. Do drop a note with the solution. We might learn something :D
The house is about 50 years overdue for a rewire, the main part having old fabric covered wiring and huge china fuse carriers. There are some flush 13A sockets fed from 5A lighting circuit, A nightmare scenario and difficult to diagnose problems. Would be immediately condemned if subjected to a safety inspection - huge fire risk!
If you have 13A sockets on a 5A circuit, could your lighting come off those and there be a loose wire not in a rose or JB but a socket?

Could the socket fuse have gone, esp. with it being 5A, taking the lighting with it?

Are all 3 fittings that are dead in the same part of the building or extension?

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Sponsored Links