Wiring help with changing switches - 1970's house

bounce08 · 21 Jul 2014

We are changing all the light switches and sockets in our living room which is inside a house built in the 1970's and so has pre 2004 wiring colours.

I took the light switch off and had a look at the wiring - there was only a red (live) and black (neutral) attached to the back of the old light switch - there was one other green wire (earth) which was tucked away further back not attached to the switch but was attached to a screw in the box at the back.

The new switch I want to fit has 3 attachment points for wires (L1,L2,L) - I followed the diagram and attached the neutral and live just like the old switch but it wouldn't work - I'm assuming that the earth needs to be unscrewed from the back of the box and attached to the right 'L' point?

Just to be clear, the green/earth was not attached to the old switch it was just at the back of the box screwed in.

Obviously if you can't tell I am not experienced at all!

AndyPRK · 21 Jul 2014

No! Leave the green wire on the metal work unless your fitting a metal switch.

What terminals have you used?

riveralt · 21 Jul 2014

You have bought a two way switch - wire it as a one way like below:

Red (live) into L1 and Black (switch live) into L2 - put a red sleeve on the black. Leave the earth (green) alone.

Read:
//www.diynot.com/wiki/Electrics:Single-way-lighting

and other similar topics.

EFLImpudence · 21 Jul 2014

A Neutral is the conductor which completes the circuit from the load back to the supply.

Wires can be anything we want them to be; they do not know what colour they are.

bounce08 · 21 Jul 2014

AndyPRK said:
No! Leave the green wire on the metal work unless your fitting a metal switch.

What terminals have you used?

Ahhh okay....they are metal switches/sockets (plating steel) with plastic socket holes/switches, here they are..

http://www.diy.com/nav/fix/electric...le-2-Way-10Ax-Black-Int-9289328?skuId=9299028

The back of the switch plate has 3 terminals for wiring. The top terminal is labelled 'L' (I left this one empty), and 2 at the bottom labelled 'L1' and 'L2' in which I have wired the neutral and live as per the diagram which also seems to show the earth/green needing to be wired in to the top 'L' terminal but as I said its screwed into the wall.

I know I'm making this sound more complicated than it is....I know I can do this I just can't figure out how to get it wired up correctly and don't want to pay for an electrician for what should be a quick job.

I can provide photos if it helps..

AndyPRK · 21 Jul 2014

I would be interested in the instructions if they are as bad as you state.

Put red into L
Black into L1

Green into the earth terminal connected to the metal

333rocky333 · 21 Jul 2014

The switch should have come with a wiring diagram and im pretty sure it wont say to use the bottom two terminals of the new switch

333rocky333 · 21 Jul 2014

riveralt said:
Red (live) into L1 and Black (switch live) into L2 - put a red sleeve on the black. Leave the earth (green) alone.

In my experiance that wouldnt work with a majority of switches

bounce08 · 21 Jul 2014

Think I'm finally getting somewhere thanks to you lot.

Finally, and just to be safe, as someone said above, I should leave the earth alone unless it has a metal switch right? The switch plate is steel but the actual switch is plastic - I take it this is okay and doesn't need earthing (as the switch itself is plastic but the surround/face plate is metal)?

Like this..

Untitled

bounce08
21 Jul 2014
1

333rocky333 · 21 Jul 2014

Is there an earth tag on the plate, again check the instructions it should either say it MUST be earthed (probable) or it may say its double insulated ( unlikely)

JohnW2 · 21 Jul 2014

bounce08 said:
Finally, and just to be safe, as someone said above, I should leave the earth alone unless it has a metal switch right? The switch plate is steel but the actual switch is plastic - I take it this is okay and doesn't need earthing (as the switch itself is plastic but the surround/face plate is metal)?

To the best of my knowledge they are all like that - I've never seen one in which the switch itself, as well as the plate, is metal. Nor, as I think 333rocky333 is more-or-less saying, have I ever seen one which did not need to have the metal faceplate earthed. As he said, the presence of an earthing terminal on the back of the faceplate would be a strong clue!!

Kind Regards, John

EFLImpudence · 21 Jul 2014

CLICK

JohnW2 · 21 Jul 2014

EFLImpudence said:
CLICK

Ah! No, I didn't mean that

. I'm very familiar with switches which have metal rockers or toggles - what I was meaning is that I have never seen any with metal-bodied switches. Have you got pics of the backs of any of the ones you linked to?

[and I do wonder how they get a reliable earth connection even to the metal rockers in ones such as you've linked to - is there some mini flexible strap attached to the back, or what?]

Kind Regards, John

EFLImpudence · 22 Jul 2014

JohnW2 said:
Ah! No, I didn't mean that ... what I was meaning is that I have never seen any with metal-bodied switches. Have you got pics of the backs of any of the ones you linked to?

No, sorry.
It would be difficult to make metal-bodied ones I would think.

[and I do wonder how they get a reliable earth connection even to the metal rockers in ones such as you've linked to - is there some mini flexible strap attached to the back, or what?]

Oh, I don't know.

JohnW2 · 22 Jul 2014

EFLImpudence said:
JohnW2 said:

Ah! No, I didn't mean that ... what I was meaning is that I have never seen any with metal-bodied switches. Have you got pics of the backs of any of the ones you linked to?

Click to expand...

No, sorry. It would be difficult to make metal-bodied ones I would think.

Indeed - and I had assumed that's why I've never seen any!

EFLImpudence said:
[and I do wonder how they get a reliable earth connection even to the metal rockers in ones such as you've linked to - is there some mini flexible strap attached to the back, or what?]

Click to expand...

Oh, I don't know.

Nor do I - I must find one and dissect it sometime! I wouldn't have thought that reliance on contact at the (moving) pivot would be 'sure' enough - which is why I was speculating about the flexible strap!

Kind Regards, John

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Wiring help with changing switches - 1970's house

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