Help! My Light Won't Work!

[spider-dan]

Hi, been a while, sorry!

I have now wired the lounge light up, having found the switch. The light now works, but flickers. The rest of the lights in the house are still not working. I am a little worried by a fourth red wire that is in the lounge pendant, this one has an earth, but no neutral. I have wired this in, but don't know whether I should of and what it's purpose is?!

Any help would be greatly appreciated!

Thanks

Lucy

 

[securespark]

You are unsure of what it does but you "wired it in"........

How did you know where to put it?

 

[JohnD]

rather than rewire from guesswork, it will be very helpful if you identify the Supply cable first, then the Switch cable (for which you will need a £10 multimeter available from your local hardware store).

Have you managed that yet?

 

[spider-dan]

The light in the lounge comes on and stays on, the upstairs lights are now working.

The light in the lounge will only come on if I turn the kitchen light on.

 

[JohnD]

I'll take that as a "no" then

 

[spider-dan]

We have found the supply cable, but the way we were given for testing the switch has no effect. Whichever pair of red and black cables we test - turning the switch on and off has no effect.

 

[JohnD]

no effect on the meter?

 

[spider-dan]

nope. Are we being very silly by testing it with the wires in the rose? Do we need to unwire it all to test for the switch?

Thanks

 

[JohnD]

To test a pair of wires, you have to disconnect them from everything else. They might be receiving power from somewhere else, or be connected through another pair of wires to a switch.

When you disconnect, wires, do a diagram first, and write on the cable sheath "1" "2" "3" or something, and write these numbers on the diagram.

Once you have identified the cables, write "supply in" "switch" Loop out" or whatever each might be on the sheath, or a little sticky label or bit of white tape.

 

[spider-dan]

Ok, we've unwired the pendant.

We've tested each of the pairs of wires using the continuity setting on the multimeter. The supply pair blew the fuse.

We have replaced the fuse wire.

The two other pairs produce no effect on the multimeter when we turn the switch on and off in the room. The other red wire has no black with it, so we can't test it.

Any ideas?

Thanks

 

[JohnD]

OK, well you've found and marked the supply (though, if you look at my earlier advice, you'll see I said

"Turn off the power, and with the meter still set to AC Volts, test all wires to make sure they are dead. then, set your meter to low Ohms, or Continuity, or 200 ohms or whatever the lowest resistance scale is. Put the light switch to the "on" position. Test across the red and black wires of each cable. When you find one with very* low resistance, turn the switch to the "off" position If the resistance then increases to approx infinity (or "continuity" indicator goes off), but returns when the light switch is turned "on" then that is your switch cable."

It is possible you have damaged the meter. If you set it to continuity and touch the probes together, do they indicate? If they do, then, with the power off, test that spare red for continuity against all the other reds and blacks (except the supply cable which you have already identified and marked) with the switch on, and see if it goes, with the switch off.

You say you have a spare red. Is this in a sheath with another red? If so, it may be the switched live return. If you have a look behind the switch (no need to disconnect the wires, but please do turn the power off!) see if it has a red and a black, or two reds.

 

[spider-dan]

Ok, having now read your advice properly we've checked the multimeter and it's still wokring fine, phew! With the power off we've tested each pair of wires and still there is no change the multimeter just reads 1. The spare red is by itself in a sheath with just an earth.

 

[Steve]

Ok, we've unwired the pendant.

We've tested each of the pairs of wires using the continuity setting on the multimeter. The supply pair blew the fuse.

<slaps forehead in frustration>

PLEASE dont tell me you have been doing this all live???

 

[Steve]

Ok, having now read your advice properly we've checked the multimeter and it's still wokring fine, phew! With the power off we've tested each pair of wires and still there is no change the multimeter just reads 1. The spare red is by itself in a sheath with just an earth.

1 what? banana? crouton? eon?

 

[spider-dan]

Wow, that is very helpful thank you. I have confessed to my lack of ability already.