Stair lights

19 Apr 2004
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United Kingdom
This has been taxing my grey matter (and my brain) for a long time.
What I have A light at the top of the stairs and one at the bottom. The switch at the bottom controls the bottom light but not the top. The switch at the top controls both the top and the bottom lights.
What I'd like Both switches to control both lights. I just cannot figure out how this would work. There are obviously two power supplies at the moment. Do I have to cut this down to one supply.
This has become a bit of an obsession with me at the mo, so any help would be appreciated. [/u]
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In simple terms, what you need to do is run a 3 core and earth cable from the terminals of the switch that controls the upstairs light to another switch at the foot of the stairs.

If you have a 2 gang switch upstairs (one switch plate with two rockers on) then it will be ready to extend, having three terminals.

You should have a live feed and a switchwire in the terminals of the switch that controls the upstairs light, using Common and either L1 or L2.

When adapting a one way circuit to two way in this situation, you would remove the wire(s) from Common and place them in the other "L" terminal, 1 or 2, depending upon which one is already used.

You should now have the live feed wire(s) in L1 and the switchwire in L2 (or vice versa).

The new cores from the 3 core and earth cable go as follows: the red in the common on its own, and the yellow into L1 and blue into L2, along with the original live feed and switchwires.

At the other end, the red goes to common of the new switch, and the blue and yellow to the corresponding terminal. (IE if you put blue in L2 upstairs, put blue in L2 downstairs).

Your new switch position can either be a separate switch or if you have room in the back box, you could replace the existing one gang that switches the downstairs lamp with a two gang.

Also, to help you visualise what I have written, search for two way lighting diagrams on this site.
This is less complicated than explained - Joat wants the one gang switch at the top and the one gang switch at the bottom to switch on both lights.

Yes you need to remove one of the supplies then do a 2 way switching circuit which supplies one of the ceiling roses which is paralleled to the second ceiling rose.
Thank you for the replies. I was looking at the 2-way switching diagram earlier and can now understand how to apply it in my case. It all just proves there is no substitute for experience!
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Inspector - think you have misread the original post. Joat wants to be able to switch both lighting positions on from either end of the staircase, but to keep them independent of each other.
It's probably a badly connected two way circuit already.

Joat, have you removed the switch downstairs, the one that only operates the downstairs light?

How many "wires" are in there? If the switch is a one way switch, then there will be one red and one black (possibly two red) and an earth wire.

However if the switch was originally wired as two way, and a connection has been removed, come loose or the switch faulty, then the switch will have THREE "wired" terminated into it. Usually Red, Yellow and a blue.

Are you able to identify which you have downstairs, and at the upstairs switch as well.

If you can do this the replies can be a little more accurate then.
I agree there is more to this than meets the eye, but a problem with the switch wiring would not allow both lights to be switched from one position and not from the other. Surely if there was a problem with the switch wiring, both lights would react in the same way?

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