Electrics - Light in one room suddenly not working

Electrics - Light in one room suddenly not working

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sal 965

Original Poster:

549 posts

140 months

Tuesday 24th November 2009
quotequote all
We live in a newish three storey house and off one of the top floor bedrooms is a small room/cupboard with a standard ceiling light. For no reason it has recently stopped working so obviously i changed the bulb. No difference. Changed the light fitting. No difference. And finally changed the light switch. No difference.

Does anybody have any clue what may be the cause of the problem as everything else in the house is working on that circuit.

Simpo Two

68,896 posts

194 months

Tuesday 24th November 2009
quotequote all
Silly question but did you test the new lamp elsewhere?

sal 965

Original Poster:

549 posts

140 months

Tuesday 24th November 2009
quotequote all
Took the fitting down from another room after checking it worked

FourWheelDrift

74,015 posts

213 months

Tuesday 24th November 2009
quotequote all
Cut supply possibly? Have you been knocking nails/screws or drilling anywhere in the walls recently?

sal 965

Original Poster:

549 posts

140 months

Tuesday 24th November 2009
quotequote all
No nailing, drilling etc.

Worked one day and not the next. I can only guess a wiring issue so my have to venture into the loft to see if anything becomes clearer.
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NotNormal

2,072 posts

143 months

Tuesday 24th November 2009
quotequote all
Worth checking behind the light switches in the other rooms. I had a similar issue last week in that the continuation power supply leading from one room to the next had dropped out the fixing point on the switch. (i.e two cables into the one grub screw location). Took me a while to suss but obviously someone hadn't tightened the grub screw up or even poked both wires equally in the hole).

SeeFive

6,101 posts

162 months

Tuesday 24th November 2009
quotequote all
I'll caveat this with "I am not Part P" and by the sound of it, nor are you. We should seek professional help with such things.

I had this once before, where a light suddenly stopped working. It turned out to be a fault in the previous light in the circuit, and I can't remember which, but either the ring live or common not getting to it.

If it is the last light in the circuit, then this could be it. If it is not the last light, then it will not as the others should go out too. If you have tried two separate lights since it failed, the chances are that it is in the ceiling. If you are not confident with electric, or not sure about your lighting circuit, get a sparky in. It's better than electrocution.

If you are brave, to start, get a meter or one of those lightly up screwdrivers, and make sure that you are getting a live from the ring (where all the reds or browns are joined together in the rose). Make sure you are dry and wearing rubber soled shoes at least. THIS WILL GIVE YOU QUITE A KICK IF YOU ARE NOT ENSURING THAT YOU ARE NOT IN CONTACT WITH ANYTHING THAT IS ACTUALLY TOUCHING THE WIRE. ENSURE THAT YOU ONLY HOLD INSULATED PARTS OF THE TOOL TOUCHING THE WIRE. Be very careful. You should not need to undo any connections to test this.

Also, make sure you have constant live at the switch (probably the connector in the switch marked COM, and not L2/L1 - these are the switched live outputs). Then make sure you are getting a switched live at the bulb - this will be the wire out of L1/L2. In one switch position it will be live, the other switch position not. SAME WARNING AS ABOVE. Again, do not undo any wires in the switch. At this point you have tested the live feed for that lamp.

If you haven't got a live in the rose, then it is in the ceiling somewhere between this lamp and the previous one in the circuit - my guess is a loose connection on the reds / browns in the previous rose.

If you haven't got live at the COM in the switch, then it is between the rose and the switch.

If you haven't got a switched live at the bulb, then it is the wire out of the L1/L2 side of the switch switch to the bulb.

If this is all ok, it could be the common wire which is the blue set of wires - again, maybe a loose in the previous rose on that bunch of wires. This may need a better meter to test for sure, putting a line test from the previous rose or, in if you don't know how to do this, get a sparks in.

Worth a look I guess. I bet it's a loose on the common / live ring in the previous rose.

ETA - Assuming that you only have one light and one switch in the room.

and again for typos...

Edited by SeeFive on Tuesday 24th November 16:52


Edited by SeeFive on Tuesday 24th November 17:24

Wings

5,071 posts

144 months

Tuesday 24th November 2009
quotequote all
I had the same problem with a hallway light not working, where the hallway bulb had blown, bad earth in the bulb, causing a flash back, short in the wiring of the previous ceiling rose on the lighting circuit. Mind I have also had the daughter place a picture nail in the wiring from the light switch.

NDA

14,234 posts

154 months

Tuesday 24th November 2009
quotequote all

What voltage is the light? Some are 12V and use a transformer which will be further along the wiring from the lamp.

It could be this....


sal 965

Original Poster:

549 posts

140 months

Tuesday 24th November 2009
quotequote all
Sorted.

One of the black wires had come out of the multiplug in the bedroom light fitting (last one before the cupboard) as i mustn't have quite caught it enough when i put the light up nearly four years ago. At least i should be good for the next four years.

Cheers for the tips everyone.