2 way switches

[shanepaul53]

Hi,

Would like a little advice on 2 way switches. Currently, my hallway and stairway share 2 lights controlled by 2 switches at either end of the hallway only. I would like to be able to switch the lights on from the bottom of the stairway as well because presently I have to go up and down the stairs in the dark which is unsafe. The existing lights are enough to light the stairs when on so there is no need to add additional lights. I am thinking of adding a third switch at the bottom of stairs to control these same lights. Using 3 core + earth cable, is it ok to connect another switch to the 2 way system already installed? and if so, is the wiring the same us it would be normally.

I welcome any comments,

Thanks

 

[viewer]

Hi,
Checking first that the upstairs and downstairs circuits are one and the same, then you need an intermediate switch. It depends a little on how your two-way works, but basically it has 4 terminals and sits in the circuit between the two existing switches (physically where you want it). You take the 2 wires from one existing switch to one side and the 2 from the other existing switch to the opposite side. See the Wiki. From your description, it may be easiest to swop one of the hallway switches for the intermediate, then put the other as your new one. You don't mention switching from the top of the stairs, which I assume you'll need, so just move the system on one notch - i.e. put in another intermediate with the two-way at the end and so on. There is no limit to the number of intermediates. You'll need to work out (draw it out is easiest) the existing circuit in order to cut down on the holes etc and if using junction boxes, then these need to be accessible later on.
HTH
V

 

[shanepaul53]

Hi and thanks for your reply. To paint a better picture of the situation, please read the following.

At the bottom of the landing is a single light and 2 gang 2 way switch. One switch turns on the light at the bottom of the stairs. At the back there are two wires running into one of the switches, this is because the light at the bottom of the stairs can be turned off from a 2 gang 2 way switch at the top of the landing. The other switch on this 2 gang 2 way switch downstairs not connected to anything, and therefore does nothing

The 2 gang 2 way switch at the top of the stairs turns the light at the bottom of the stairs on/off as stated above and the other switches on/off the lights in the upstairs hallway.

At the other end of the hallway is a single (1 gang) 2 way switch which also turns on/off the lights in the hallway. As you can see, there is no way to turn on/off the lights for the hallway from the bottom of the stairs which would provide better lighting for the stairs.

I have established that the circuits for upstairs and down are separate lighting circuits. I can easily lay a wire from the 2 gang 2 way switch upstairs to the 2 gang 2 way switch downstairs but as the hallway lights are already controlled by a 2 way system, and therefore was concerned about adding a third and need to be certain that the wiring is the same as if the single 2 way switch at the other end of the hall wasn't there.

Hope this makes sense!!!

 

[viewer]

Hi,
I did get a bit confused - can we call the downstairs horizontal passageway "the hall" and the first floor horizontal passage "the landing"? My brain fails all too easily if asked to work out two things at once. Most important - because there are two separate circuits, then you cannot simply join them. It might work, but you would be using a borrowed neutral; i.e. power from one circuit would 'return' through the neutral of the other. Potentially dangerous. This means that you must decide whether to use the upstairs or downstairs circuit to control the top of the staircase light.
I'm not sure about your description of the control of the two hallway lights. Looking at the 2G2W switch in the hallway near the stairs: Are there two wires into each of the L1/L2 connections? If so this suggests that you have power supplied to com on the 1G2W hallway switch and to com on the 2G2W landing switch. The hallway lights are fed from the com on the 2G2W switch in the hallway. It would also explain why the landing light is not included (borrowed neutral problems). If we're right so far, then you have options:
1. Disconnect the landing light from the upstairs circuit and join the lamp directly to the most accessible hallway lamp.
2. Put a new light in the mid staircase area and connect to the hall lamps.
If you have the type of staircase with a floor which juts out halfway up, then the latter option would be easiest as you could run the cable between ceiling and floor from the hallway light to the vertical wall in the staicase without destroying the plasterwork.
HTH
V

 

[shanepaul53]

Thanks for your feedback, it beginning to make a bit more sense. I went to an electrical supplier yesterday and spoke with an ex electrician. He retired some years ago so might be a little out of sink with current regs. We basically came to the same agreement, similar to what you suggested previously, which is to replace the 2G2W switch upstairs which controls the hallway and landing lights with a 2G2W + intermediate switch so that i can control lighting from 3 points in my home. I am now researching this on various websites to make sure I get no surprises when I come to carry out the work. I also value any suggestions you have on this. With regards to keeping the 2 lighting circuits separate, the upstairs circuit will feed the switch downstairs which is understood to be potentially dangerous however, to protect the safety of third party maintenance personnel in the future, I have been told to write "2 circuits" on the back of the switch faces used to carry out this work...is this adequate or are there better ways to maximise safety?

 

[bernardgreen]

Put an explanatory note in the Consumer Unit as well saying which MCBs are involved on the two circuits to the switches.

 

[shanepaul53]

Thanks, will do, infact at the moment the MCB's are not labelled at all which is something I intend on doing so I don't have to flick all the MCB's to know which circuit is what. I find it easier to isolate power completely when doing any kind of electrical work. With respect to what I have suggested regarding changing the 2G2W upstairs to one which is intermediate, does this in your opinion sound like a suitable solution?

 

[viewer]

Sounds good. Remember that we are guessing a little and assuming that the system is logical so you need to confirm the physical truth. Your electrician friend will know how to do it if you're not familiar with a multimeter (if you're not - now is your chance!). Any change in the regs won't have altered the logic and he'll probably have seen many circuits like yours if he worked in the area. Again, I'd suggest testing and drawing the circuit on paper to be sure that you're sure of all connections and are choosing the easiest routes.
Best of luck. Oh and draw every switch/connection and label every wire you disconnect for testing. Seems like extra work, but it saves much worry later on.
V

 

[shanepaul53]

Thanks Viewer, for all your help and recommendations.

I carried out the work 2 nights ago and everything was a success. I achieved what I wanted to achieve. Having great resources for schematic diagrams and people in the trade to ask questions makes the work a lot easier. It was actually quite straight forward in the end but as I am learning it's important to do your research and take your time getting an understanding of the wiring within the house. I don't want to end up on the "Hall of Shame".

Thanks,

S