Light wiring problem

[BrokenHandle]

I posted something last night regarding a junction box I replaced without noting the wiring. I've been out and bought a mains test screwdriver and can now state categorically which wires are live and which are not.

Have as follows - 3 cables which I will call 1, 2 & 3. 1, must be coming from power source as this is the only red wire that mains tester showed as being "live".

I connected this live red to the reds of 2 & 3, one of which must be the switch and one must go on to the next light. Once I did this the black wire of cable 3 became "live" immediately and the black wire of cable 2 became live when I flicked the switch.

I assume therefore that cable 2 is the switch cable and cable 3 goes on to next light.

I then connect the blacks of 1 & 3 together and connect them to the neutral wire of the new light. I take the black from the switch and connect that to the live wire of new light.

The light nearest the junction box stays off and the remaining three are on permanently, the switch, whether off or on makes no diference to any of the lights.

I am confused as really thought the above should work. I do recall that when I took old junction box off, two of the reds were connected together and the third was seperate from them (can't recall where it was connected).

Has the electrician who did my extension put a switch on the negative side of the circuit? Is this why I cannot get to work? How do I wire up as he had, so that at least the lights go off and on. If I can get this far and he has done it wrong, I can get a proper electrician in to check it all over and re do, but really want to get the lights back to the way they were before I quit.

Any ideas would be great.

 

[Steve]

If 1 is the power source, as your testing shows it is, then this needs connecting DIRECTLY to the power to the next light - cable 3. (The reason black3 showed live when red3 was connected was because there must be a switch closed somewhere and so is passing voltage through on the neutral. So this almost certainly goes to the next light.)

Cable 2 is the switch wire. So this needs connecting between the other 2 lives and the live of the new light.

So it does sound like everything is wired correctly.

However, i must point out that your testing method does not exactly fill me with confidence. Neon screwdrivers are notorious for giving false readings and lighting up in mid-air. The correct way to measure voltage and continuity is with a correctly rated multimeter. Owning a multimeter and knowing how to use it will greatly increase your chances of success with this type of electrical work. If you dont own a multimeter i suggest you call an electrician, he will be able to sort this problem within half an hour, if that.

 

[BrokenHandle]

Thanks for the reply. I got frustrated that things weren't working even though I was convinced I had it wired right, so went through connections one by one. Very unprofessional I know.

The end result is that lights work in the kitchen as they did before, connections in the junction box were cable 1 red to cable 2 red. Seperately cable 2 black to cable 3 black and down to new light. Seperately cable 3 red to cable 1 black and down to new light.

I looked in the loft at the wirng the same electrician had done for me in the bathroom and that was set out precisely as all the diagrams show on this site.

I am going to get a friendly electrician to look at the kitchen electrics shortly as really want to understand why this works the way it does.

Thanks