DESPERATE HELP NEEDED!

[diyicant]

Went to fit a new modern light fixture into my flat. Didn't want to have all power off in flat just lights. So isolated it so no lighting worked. Got to work. Got fixture up and was ready to have break. So flicked switch to have lights back on. Did that and now no light will work in house?

What have I done , why has it done this?

 

[EFLImpudence]

You have not connected the wires correctly.
Have you blown a fuse or tripped the mcb?

All you had to do was copy what was already there but for some reason people don't.

This comes up nearly every day.

//www.diynot.com/forums/viewtopic.php?t=37582

 

[diyicant]

No I haven't connected the lights yet, thats not the issue! I turned lights off through the fuse box whilst doing work turned back on. Now lights won't work in flat!

 

[diyicant]

thats not the issue, i switched fuse off in fuse box whilst doing work. Switched back on now no lights work!

 

[dannyboi2003]

Your lights don't work as they are each connected one after the other from the fuse box, the one you are changing is probably the first on the circuit which is why none of the others work, they will not work until you reconnect the wiring to the new fitting.

 

[diyicant]

Thank-You!

Makes sense!

Altough you were right didn't take note of where orignal wires went in old fixture. Any ideas?

Uploaded pics in my library if you could take look would be much appreciated!

 

[xdave]

Your pics:

Untitled

• diyicant
• 19 Feb 2013
• 1

Untitled

• diyicant
• 19 Feb 2013
• 1

You should not turn the power back on when bare wires are poking out of your ceiling - it is highly dangerous as you may forget that the circuit is live when returning to it, or someone else may come into contact with them. Always terminate unused wires as soon as you finish disconnecting them. If that picture really shows how it is then isolate that circuit again immediately.

 

[diyicant]

it has been isolated which wires go where?

 

[xdave]

You really should have noted which cable went where before disconnecting the old fitting. You have three cables present. One will likely be your switched live and a permanent live that goes to/from the light switch. The other two will be carrying the power from your fuse box to the light fitting, and then taking the circuit on to the next fitting. They are normally called loop in and loop out respectively. You need to identify which cable is which.

Do you have a multimeter? With the circuit dead you need to test for continuity between the red and black wires in each cable's pair with the light switch in the "on" position. When you have continuity then you have identified the switch cable. You can use a handheld torch to perform this test by bridging the switch with the two wires you are testing to complete the circuit. You must ensure that the circuit is properly isolated and that no one is able to switch it back on without you knowing.

Once you've found the cable that carries your switched live then the other two will be the loop cables. Confirm against false-positives by proving false with the other two cables. Numbering the terminals on the new fitting from left to right as orientated in your photo then you would wire:

- both loop reds to terminal 1.
- both loop blacks to terminal 2.
- switch cable red to terminal 1.
- switch cable black to terminal 4.
- All the earths (covered green and yellow) to terminal 3.

The cable to terminal 4 should be covered with red or brown tape, tubing, or labelled cleary with words to show it is a switched live.

That would connect it as per the 1 way lighting using chock block diagram in the FAQ (linked to above).

 

[EFLImpudence]

You will need a continuity tester to determine which cable goes to the switch.

POWER OFF.
Probes on a red and a black from one of the cables.
If they have continuity when the switch is on and not when off - sleeve this black with red.
If not try another cable.

When you have the correct cable this black is your 'switched live'
Connect this to the brown of the lamp.

Connect the other two blacks to the blue of the lamp.

Put all three reds in a separate connector but do not connect to anything else.

Connect all the earth wires to the new fitting.

 

[diyicant]

don't feel comfortable doing this.

 

[xdave]

If you don't feel able or have the tools needed to test for continuity then you'll need to either ask a neighbour if they can assist or call an electrician out to do it for you. I am not aware of any other safe way to connect those wires back up, even just to bring back your other lights, without risking a dead short which will be dangerous and could cause permanent damage to your wiring.

If you don't have a multimeter or similar device then the torch (or other battery operated bulb test) is safe to do as long as the circuit is isolated, but never attempt it if you aren't confident. The power must be switched off at the fuse box and the light switch on the wall/ceiling switched on. Work through each pair of wires together and hold one of the wires to one side of the torch switch and one to the other. If the bulb comes on then you have a closed circuit so that is the switched cable. If the torch is one where the button is on the end of the torch, behind the battery, then it is very simple to do - one cable to the rear of the battery and the other to the metal strip that will run up the body of the torch alongside the battery. If the torch has a switch on the side of the body then it is harder to do but you could probably work out how. It may just need the switch turning on first and then touch the wires as above. Think back to school - did you ever make a fuse tester with a battery and an LED? It is the same thing.

 

[diyicant]

£80 later we have lighting and 3 new light fixtures up

 

[Scoby_Beasley]

In an hour? I'm impressed!! Give us a bell if you want owt else doing!!

 

[xdave]

Well done. Did you get an electrician to help you?

If you want to change over a light fitting or switch in the future then be sure to take a photograph before you disconnect anything and label each of the wires with a bit of masking tape and a pen. Then you can sit down and work out which wire will go where on the new accessory before you fit it. You can also more easily refit the old one if you get stuck.