Single switch wiring to double switch wiring causing issues

[PingCrosby]

Hi,

I am having some issues with wiring. A friend replaced a switch in my house with a new one and unfortunately I no longer seem to have a working system. He said it wasn't working but just assumed my bulbs had blown. After replacing the bulbs....I still have no garage or outside lights.

The switch controls an outside light, it receives power direct from the CU before forwarding current to another double switch located elsewhere. The double switch located elsewhere switches on/off a garage light and the outside light.

What should happen is - (a) Single switch turns on/off outside light, (b) Double switch turns on/off garage light and turns on/off outside light.

Unfortunately, no matter what combination i use to wire up the new light circuit, I no longer have a working garage light nor outside light using either the double switch or the new single switch

Can somebody help me. I have not touched the double switch at all.

I have a wiring diagram, although the single switch wiring is show incorrectly, i did not want to just show hanging connections. The crimped "commons" were done previously and are not my doing.

I am assuming (obviously wrongly) that i need to wire L1, L2 and CN as i need a 2 way switch. I used this as my guide http://2wayswitch.com/2-way-switch-wiring-diagram/

Thanks for any help.

Badly drawn wiring diagram

• PingCrosby
• 10 Jun 2008
• 1

The Single switch L1, L2, CN wiring is guesswork and does not work .....

Double switch front

• PingCrosby
• 10 Jun 2008
• 1

Inside double switch

• PingCrosby
• 10 Jun 2008
• 1

sorry about the over exposure

Inside double switch

• PingCrosby
• 10 Jun 2008
• 1

even worse flash exposure

Inside Single switch

• PingCrosby
• 10 Jun 2008
• 1

No matter what combination of L1, L2, CN wiring i try using the switch i cannot get a working...

*) Note I tried bypassing the switch as a test and wired all 3 wires together. I thought this would send power regardless of the double switching. No success...

**) What would have been the correct way of creating a bypass on the switch are there any techniques i can use to test that power is getting to the double socket. I was going to use a multimeter and a probe, would this be the correct method??

Lots of questions..

Thanks again

 

[holmslaw]

..

 

[PingCrosby]

Thanks for your response,

>> The installation is a dangerous lash up.
I don't disagree it is a mess.

>>It could never have worked as your description - your missing a wire.

My wiring diagram could be incorrect, but the pictures should be correct. It used to work though; what wire do you think i am missing? - I can go and take a look. Which part of my description raises alarm bells? - I can double check!

>>The cable from the inside switch is using the earth wire as a neutral.
>>Therefore there is no earth at the light switch.

Do you mean in the "double light switch", does this necessarily need an earth as its an all plastic setup?

Thanks for your help

 

[holmslaw]

..

 

[johno12345]

Agreed, this is less than ideal!

There arent enough cables present to do what you want. Whether or not it worked before is irrelevant! You simply cannot use the earth as a live conductor! The best you could manage out of that situation would be to have a dusk till dawn /pir outside light controlled from the garage and link the cables together where the inside switch is

Forget the 2 way setup.

Incidentally, the cable feeding the outside light looks like it might not be suitable.


It might be time to get an electrician in... If the lightswitch in the garage is near to the lightswitch inside the house it shouldnt be too big a job for him.

 

[dannyboi2003]

There are enough cables between the switches and i can see how it worked before, however as its already been mentioned using the earth (even as a neutral) as a conductor is not permitted. I'm not willing to say how it was wired as then its very tempting to leave it as it is and forget about it. If you can replace the cable between the switches with a Three Core & Earth that would be much safer.

Anyway just to clarify, it would have worked before but its time to re-wire it properly. i'm also not keen on the cable that runs to the outside light, can you post a pic of it so we can see what type of light it is?

All the best
Dan

 

[PingCrosby]

I am not disagreeing with any sentiments at all here and i had my doubts about the use of the earth as a live conductor.

I have already decided i will be changing the cabling there are more (you haven't seen the rest of the cabling) issues.

>> There arent enough cables present to do what you want.
>> Whether or not it worked before is irrelevant!
>> You simply cannot use the earth as a live conductor!

Its only relevant to me in the sense of, "it used to work and now i am told it never worked because its an impossibility!", I am not arguing the fact that its dangerous etc, but I am confused as to what exactly makes people think that it could never have worked *ever*.

This is leading me to suspect I am giving the wrong information and that my wiring diagram 'albeit' the single switch wiring (which I know was wrong) and the cables I have labelled as "from CU", to "garage light", to "oustide light" are incorrect.

>>The best you could manage out of that situation would be to have a >>dusk till dawn / pir outside light controlled from the garage and link the >>cables together where the inside switch is

This is kind of what it does. The PIR is switched on/off from the garage and the inside switch. The garage light is switched only from the garage.

 

[PingCrosby]

Thank "dannyboi2003", I will do as you suggest.

Thankyou for clarifying that i am not going insane. I was beginning to think I was posting misinformation.

 

[holmslaw]

..

 

[johno12345]

Its only relevant to me in the sense of, "it used to work and now i am told it never worked because its an impossibility!", I am not arguing the fact that its dangerous etc, but I am confused as to what exactly makes people think that it could never have worked *ever*.

I only commented on that because I often spend hours at work discussing how things worked before when we are going to do it in a totallly different way.

I would:

Link the cables in the house together and install a blanking plate or a DP fused spur for isolation purposes (Not strictly necessary)

Install a 2 way switch in the garage, one for the garage light, one for your dusk till dawn/PIR light.

Leave it at that. Remembering that the neutral shouldnt be connected to the lightswitch on any terminal, it can be connected in the back of the switch box in a piece of terminal strip.
Also remember that the earths need connecting through all the way to the last section of cable and to the lights if they provide an earth terminal.

Replace the cable to the outside light with something more suitable.

If you wire it up like this you should be able to follow the wiring diagrams in the wiki.

 

[PingCrosby]

I am just looking at the photo of the wiring and maybe I have given false information.

Looks like the double switch is LHS -> Garage, RHS ->Outside light, the opposite way to which i annotated. (looking at it from the front)

Sorry for the confusion

 

[PingCrosby]

The cable going to the outside light is 2 core and this **will** be replaced. I am particularly concerned that this is not earthed.

From the switch, the cable runs directly through the wall to the light mounting plate.

I am in the mist of replace this cabling anyways.

So.......for a similar setup using 1 single switch and 1 double switch using the correct cabling (4 core for the link wire and 3 core cable for the outside light) does anyone know where I can find a suitable wiring diagram.

Thanks for all the help so far.. btw

 

[dannyboi2003]

Asolute nonsense Please explain how the garage light can work (all the time) without a permanant live at the switch.
My post above explains how the 2 way could have worked.

Plese tell us your secret.

Look at the picture of the double switch closely and you will see the garage light forms no part of the outside light circuit what so ever. Originally the garage switch would have been a single switch just for the garage light with only a "live" and switched "live". This is the cable coming down to the switch through the capping on the wall, the garage light is probably wired using the standard loop method meaing only a single switch wire is dropped to the switch. Then along came someone and lashed up the outside light circuit (replacing the single switch for a double), the grey t&e to the right of the switch originating from the single switch inside is carrying the neutral (through the earth core) and the two "live" strappers for the outside light circuit, the white 2 core flex then goes to the light.

Also there IS a valid earth at each switch, just not between them as its been used as the neutral conductor for the outside light. As for it being dangerous and to switch it off, umm slight over re-action, its far from ideal but it isnt going to set the house on fire or kill anyone!

As i said look again at the double switch and you will see the garage light and outside light circuits are completely independent of each other

All the best
Dan

 

[dannyboi2003]

The cable going to the outside light is 2 core and this **will** be replaced. I am particularly concerned that this is not earthed.

From the switch, the cable runs directly through the wall to the light mounting plate.

I am in the mist of replace this cabling anyways.

So.......for a similar setup using 1 single switch and 1 double switch using the correct cabling (4 core for the link wire and 3 core cable for the outside light) does anyone know where I can find a suitable wiring diagram.

Thanks for all the help so far.. btw

Hi Ping,

There wont be a specific diagram for your setup as its not going to be a standard configuration. I can post how to do it a bit later when i get home if thats ok, unless someone else does before then.

All the best
Dan

 

[ban-all-sheds]

Its only relevant to me in the sense of, "it used to work and now i am told it never worked because its an impossibility!", I am not arguing the fact that its dangerous etc, but I am confused as to what exactly makes people think that it could never have worked *ever*.

Maybe they assumed an implied "could never have worked without doing something criminally stupid".

Because that is what has been done here. I don't use that term in any careless or exaggerated sense - using the cpc as a live conductor is stupid, and it is a criminal offence punishable by up to 6 months in prison and/or a fine of up to £5,000.