Sparkies please-2 way switching

Soldato
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25 Nov 2009
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Evening guys... this has got me scratching my head :/

I've been doing some work in my house, replacing ceilings and the likes. I've come to wire the switches for the hallway lights and I've been stumped.

Ive got 1 ceiling rose upstairs and 1 downstairs. 1 switch at the bottom one at the top obviously with the idea being that either switch will turn both lights on or off.

I just cannot get it to work properly though... I've got it so that there's always one light on. Either up or down, not both. The switching of either up or down switches the lights over. Still only one illuminated!

Upstairs switch has 3 core +E cable and a twin +E.
The twin goes to the upstairs ceiling rose.
The 3 core goes to the downstairs switch.
The ceiling rose has the pendant and the twin +E from the switch

Downstairs switch has 3 core+E from upstairs and and a twin +E.
The twin goes to the downstairs ceiling rose.
The 3 core goes to the upstairs switch.
The ceiling rose has pendant, the ring and the twin from the downstairs switch.

Whats happening guys?

I'm almost sure it worked right when I bought the house but tbh it's that long ago I actually cannot remember. I haven't added or removed any circuits simply replaced the roses and switches once the new ceiling were up.

I can do a little diagram if it helps :)

lighting%20diagram_zpswsktruml.png

lighting%20detail_zpsxaikqgbw.png
 
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Soldato
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This is the old school way of doing it, I think it may no longer be right.

but consider your two switches as having two poles. Live goes into one switch, out of the other to the lights, then negative out from there as normal. The tricky bit is what you do between the two switches.

You have two wires. One running from 'up' on the 1st switch to 'up' on the second. The other the same with 'down' at each end.

This means that whichever switch you change the position on, you will either be completing or breaking the circuit.
 
Soldato
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Well in that diagram the second light would just be placed in series with the first.

The problem is that this doesn't help much as clearly you can't see where all your wiring goes and connects.

Given your description of what you've changed in the first post I can only assume you've wired up one or both of your new switches wrongly (or have bought switches which work differently).
 
Associate
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Must admit haven't seen this before sounds a bit odd

The paint diagram must be wrong or incomplete - upstairs part looks good

The downstairs switch - it shows a neutral at the rose going into the switch - either downstairs rose has another cable to give it a neutral or another cable at the switch to give it a neutral - or it is using the upstairs light when off as a neutral though the bulb filament? if so though i would expect either 1 light dimmer than the other or both glow dim?

If paint diagram is correct try this:

Take bulb out of upstairs and see if downstairs still lights up - if its doesn't chances are its using the bulb as a path to neutral

If your paint diagram is wrong then try this:
try swapping the 2 core at one end - swap the L1 with the L2 and see what happens?

so you have the switch live for both lights in L1 say - sounds like you have the switch live in L1 for 1 light and L2 for other light so when its switched they swap over etc?


If you cant get it working just run a 2 core from upstairs rose to downstairs rose - switch live and neutral and scrap the 2 core at downstairs switch just keep 3 core at that end then both will come on at same time
 
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Soldato
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Right, paint diagram is correct.

Did as you say and taking each bulb out 1 at a time made no odds... I've taken everything to bits and going through it all labeling as I go...

Plan for now is to leave the 3 core as it is and just wire one pendant to the other... That way I should have the switched live at both switches by both pendants will be fed in series... I think I've got that right... I'll draw it out and get back to you :)
 
Associate
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OK. I'll have to do a bit of head scratching to see if it's even possible to get it working with the layout you have in the paint diagram. But the 1st problem is you have no neutral to the upstairs light. It's got 2 live switch wires connected.
 
Soldato
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I'm just trying to piece back together what was already there... The only thing I can think of is whether he may have run a separate core to the upstairs rose to provide the neutral and I pulled it out thinking it was surplus as I already had the 3 core :/
Been well over a year since I pulled the ceilings down though so I can't actually remember :(
 
Man of Honour
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If you take the red/black cable out of the upstairs switch and connect it to the neutral and switched live in the downstairs rose it will work, you have to get a neutral to the upstairs rose somehow.
 
Don
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The 2 way method when you wire using singles, more so in commercial installations is done by running two strappers between the switches, then in the COM terminal at one end have the permanent live and at the other end have the switch wire in the COM terminal.

It looks like you need a neutral as said though on the upstairs ceiling rose.
 
Soldato
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Thanks for all of your input guys. I've lifted the flooring and dug holes in the wall so I could run another cable in as suggested...

Overall a simple fix to a problems that I'm struggling to see how it came to be but never mind... Job done now :)

Once again thanks for your help :)
 
Don
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Leeds
Thanks for all of your input guys. I've lifted the flooring and dug holes in the wall so I could run another cable in as suggested...

Overall a simple fix to a problems that I'm struggling to see how it came to be but never mind... Job done now :)

Once again thanks for your help :)

Just a quick one, Do not get neutrals crossed between circuits as when you isolate one it may still be live through the neutral from another circuit as it is classed as a live conductor!
 
Soldato
Joined
21 Aug 2010
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5,798
Well in that diagram the second light would just be placed in series with the first.

The problem is that this doesn't help much as clearly you can't see where all your wiring goes and connects.

Given your description of what you've changed in the first post I can only assume you've wired up one or both of your new switches wrongly (or have bought switches which work differently).

In Parallel, series would mean each light fitting would only receive 120v (240/2)
(everything in your house is wired in parallel)
As for the 2-way setup, personally I'd start again and do it properly!

Supply goes DIRECT to the (3-plate) ceiling rose, then a piece of T&E is run down to the nearest 2-way switch, this switch is then connected to the other 2-way switch with a piece of 3-core T&E. That's it job done, nice and clean.
 
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Associate
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22 Mar 2004
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701
This is the circuit diagram you need to follow using a 3 core & earth cable between the 2 ways switches.

light_2way_jb.gif


From your description, you could connect the switchwire in the existing twin cable to the upstairs light into the blue terminal on the diagram. You still need a neutral to the light though.

So long as the upstairs lights are on the same circuit, you could get a neutral from a nearby light, but ensure that the lights are on the same circuit, or it could get nasty with shared neutrals.

Edit, apologies for the crude diagram, but hopefully it shows what i mean.

jU5KvUw.gif.png
 
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