Adding A Wall Light

[bigbanana]

The ceiling lights in two of the rooms downstairs in my home are controlled from a three-gang wall switch in the hall. The additional gang operates the hall ceiling light.

I want to add an uplighter/wall light on a partition wall in a vestibule and wire it into the hall ceiling light switch so that the hall light and the uplighter/wall light are on or off at the same time - the vestibule is a bit dark right now.

As I'm not using a new switch, obviously I will need to connect the wall light using 1.0mm TW/E to the connections at the back of the switch gang operating the hall light. What I'd like to clarify is the other cable connections I need to make to the wall switch and what stuff I'd need to do the job. A diagram would be useful

Thank you

[bhg481]

You might have to take the wiring from the ceiling rose in the hall and put your new light in parallel with it. In many (most?) houses the live and neutral are looped from ceiling rose to ceiling rose through all the rooms on one floor and the switch wire is taken from terminals on the ceiling rose to the switch. In other words, there are 3 terminals on the ceiling rose; one is always live, one is always neutral and the third becomes live when the switch is "on". The bulb is wired between the second and third of those terminals and the new lamp will also need to be wired across those two.
Just to avoid confusion; if you look at the back of the ceiling rose you will think it has about 8 terminals. If you look more closely you will see that they are grouped to make connecting the wires easier so, whilst there are about 8 holes, there are only 3 different connectors.

[bhg481]

This diagram may make it clearer.

http://www.diydoctor.org.uk/projects/lights_and_switches.htm

[The Builder]

Nothing much to add to bhg's post, except to explain that the switch most likely has no neutral in it, so it can't be done from there.

In some cases a live feed (live, neutral, and earth) are taken to the switch, but probably not here. Connect into the ceiling rose. Earth; neutral, and switched live........... exactly where the existing light is wired.

[bigbanana]

Thank you both. I understand the need to wire the new live and neutral on the same connector blocks in the ceiling rose as the existing live and neutral connections. With regard to the switch cable in the ceiling rose, what happens there? Do I need to connect another length of TW/E between the switch cable connections in the ceiling rose and the same switch gang in the switch? Or will the existing switch cable alone allow me to control both the ceiling light and the wall light simultaneously as I want?

The Builder, could you explain please what can't be done from the switch because it had no neutral? I take it there's no real reason why I couldn't use the existing ceiling light gang to wire the wall light to?

Thank you.

[bigbanana]

I've been looking at the second diagram down on the this link;

http://www.ultimatehandyman.co.uk/how-to/light-fitting/light-wiring-diagrams

It seems to show that there is no need for an additional switch cable from the scenario outlined beside it. Is that correct?

[bhg481]

If the neutral and live are looped from room to room using the ceiling roses then all you have to do is to take twin-and-earth from the ceiling rose in the hall to the ceiling rose for the new light in the vestibule; live to live, neutral to neutral and earth to earth. There is no need to go anywhere near the switch - when you switch on the hall light the light in the vestibule will come on as well. There is no danger of overloading anything - it's exactly the same system as our dining room where we have 2 lights operated by the same switch.
There is a more unusual way of wiring the system, which is what the builder was talking about, which is what is shown in diagrams 2 and 3. In any case, just take your cable from the two terminals on the hall ceiling rose connected to the bulb and connect it across the new ceiling rose bulb terminals (+ the earth).

[The Builder]

bhg has explained it very well, Bananas. Don't overthink it. It's honestly as simple as that.
The reason why it's no use going to the switch is that any load needs a switched live, and a neutral to make a circuit (and an earth for safety reasons.)

Think of the lights as simply being "chained".

[bigbanana]

That's cleared it up for me. Thank you both very much for your advice.