Hall and Landing Light Switch

[thebadge]

Hi, I am trying to put on a new light switch in the hall. The old switch downstairs has 2 switches that turn on and off the light in the downstairs hall and the light on the upstairs landing. The switch on the upstairs landing is a single switch that just operates the upstairs landing light. The new switches I have bought do not have a 'common' input so I am confused as to what goes where.

Images attach should explain....

The two commons are connected with their own separate red wire.

the L2 on the top in the picture (black) comes from the same white external cable as the red that goes into the common at the bottom, whereas the second black and red go into the L1 and L2 on the bottom.

Do I have the wrong switch? (apologies if this has been previously answered!)

Untitled

• thebadge
• 20 Jun 2011
• 1

Untitled

• thebadge
• 20 Jun 2011
• 1

 

[ban-all-sheds]

The holes at the top are the Commons.

Note that your old switch has the terminals laid out as per this:

//www.diynot.com/wiki/electrics:twogang

not as per your new one - so play close attention, and mark which conductor goes where before you remove them.

Do the cables have earth cores? If so, these must all be connected to the earth terminal on the switch, and ideally you should also run a short flylead from there to the earth terminal of the back box. (Take a short length of earth core from some flex if necessary.)

If you have no earths then you must not use that switch.

 

[TicklyT]

The terminals marked 'L' appear to be the Common terminals on your new switch.

Note the terminals of the old switch are arranged in two triangles, with the top left and top centre terminals associated with the bottom left terminal, and the top right associated with the bottom centre and bottom right terminals. You should be able to make out a diagonal line moulded on the back of the old switch identifying the division.

You will also need to connect the earth wires to the earth terminal on the new switch. If no earth wires are present, (not uncommon in older lighting wiring) you cannot use switches with a metal faceplate (or any light fittings that require an earth connection either)

The new switch has both units mounted the same way up.

If one of the new switches works 'upside down', reverse the wires in the L1 and L2 positions of the offending switch.

 

[thebadge]

Thanks. Both cables have an earth which is currently connected to the existing back box -

Untitled

• thebadge
• 20 Jun 2011
• 1

Do I need to run a short length of earth flex from the back box to the earth point on the new switch?

 

[jj4091]

Yes, or better still connect the earth to the switch body & run a wire to the back box.

 

[thebadge]

Perfect thanks. Rewired the new switch in and swapped the earth from the back box to the switch body and then ran an earth (from old kettle lead) from that to the back box. Switched the electrics back on and all working fine....thanks very much! (Wife happy too....always a bonus!)

 

[ban-all-sheds]

Do the cables have earth cores? If so, these must all be connected to the earth terminal on the switch, and ideally you should also run a short flylead from there to the earth terminal of the back box.

Thanks. Both cables have an earth which is currently connected to the existing back box -
.
.
Do I need to run a short length of earth flex from the back box to the earth point on the new switch?

 

[cumbriahandyman]

Do the cables have earth cores? If so, these must all be connected to the earth terminal on the switch, and ideally you should also run a short flylead from there to the earth terminal of the back box.

Thanks. Both cables have an earth which is currently connected to the existing back box -
.
.
Do I need to run a short length of earth flex from the back box to the earth point on the new switch?

 

[jj4091]

Do the cables have earth cores? If so, these must all be connected to the earth terminal on the switch, and ideally you should also run a short flylead from there to the earth terminal of the back box.

Thanks. Both cables have an earth which is currently connected to the existing back box -
.
.
Do I need to run a short length of earth flex from the back box to the earth point on the new switch?

To be fair I missed that too Sorry.