Problems Adding New Light to Lighting Circuit

[Stalemate]

Hi,

I've recently wired a new light to my utility room, and I want to join the new light to the existing lighting circuit with a junction box.

I've located two cables that were on the lighting circuit that I want to connect the utility light to.

I cut the first cable and then connected it back together along with the new utility room light cable using a junction box. After doing so, the utility room light would only work when the lounge light was off. So then I took out the utility light cable so it was back to how it was when I started.

I then did exactly the same thing with the second cable. This time, with the utility light cable connected, the utility lights would only come on when the lounge lights were on.

I have no idea why this is happening or how I can wire it up so it all works correctly. I've looked on this site and others and my electrical book, but I'm not any wiser for it. Any ideas?

 

[bernardgreen]

I have no idea why this is happening or how I can wire it up so it all works correctly.

Why do so many people assume that any cable can be cut and used for a supply.

The first cable you cut was the cable to the switch.

Ask questions BEFORE you cut wires.

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

 

[Stalemate]

I have no idea why this is happening or how I can wire it up so it all works correctly.

Why do so many people assume that any cable can be cut and used for a supply.

The first cable you cut was the cable to the switch.

Ask questions BEFORE you cut wires.

Read the wiki //www.diynot.com/forums/viewtopic.php?t=37582[/QUOTE]

Thanks for the reply. I take your point.

I looked at the wiki, specifically the diagram for single way light via a junction box. Is the 2nd cable I cut definitely a power cable? If so, why is everything not working correctly when I use a junction box to connect the 2nd cable to the utility room light?

 

[bernardgreen]

The second cable was the cable to the lounge light, it will have a neutral and the switched live for the lounge lamp.

There is a third cable somewhere that is the feed with permanent live and permanent neutral.

If you trace the two cable you have cut back to where they met you will ( should ) find a junction box. The cable you need will be the third cable to that junction box. That will be the feed bringing power to the lounge lamp and switch cables. There may be a fourth cable taking power to the next lamp.

Or you may find many more cables in the junction box if all the lamp cables and switch cables are jointed in a multi-way junction box.

Or you may not find a junction box if the person who installed the electrics did not follow the rules and put the junction box where it cannot be found.

 

[Stalemate]

Thanks for your help.

I am trying to avoid pulling up loads of carpet and floorboards, and was hoping one of those two cables would be correct.

 

[Taylortwocities]

I am trying to avoid pulling up loads of carpet and floorboards, and was hoping one of those two cables would be correct.

Sadly you may not be able to avoid this, unless you can better identify where the cables are routed to.

 

[Stalemate]

I am trying to avoid pulling up loads of carpet and floorboards, and was hoping one of those two cables would be correct.

Sadly you may not be able to avoid this, unless you can better identify where the cables are routed to.

I've located a lighting cable that I'm pretty sure comes from my consumer unit. I'm quitely confident that this'll will (finally) do the job. If that is also no good, then I really will have to start ripping up the whole house. Fingers are crossed.

 

[ban-all-sheds]

These problems and questions show two things.

1) You're fiddling with your electrics when you don't actually understand how it all works.

2) You don't have the appropriate tools, in this case a multimeter to allow you to identify cables rather than guessing what they are.


Why do you think these are good ideas?