I am trying to replace an old light switch for a dimmer switch.
The switch is a single and is for one light only although the light has
another switch for it on the other side of the room.
The old wiring system has :
Cable A - Yellow, Red, Blue, Earth
Cable B - Red, Black, Earth
So the wiring goes to the socket thus:
L1 - Yellow (from cable A)
L2 - Red (from cable A) - Red (from cable B)
L3 - Blue (from cable A) - Black (from cable B)
I clearly have the Earths sorted but I am a tad confused how to re-locate
the wiring to the new socket which has the following labels for the wires:
Downward arrow (Live)
Can anyone explain how the wiring should be distributed to the new socket.
Many thanks for your time and consideration.
What you describe seems like a standard 2way light so first you need to
ensure the new switch you have purchased is to replace a 2way switch (some
are only 1 way)
It should have 3 connections (not including the earth terminal)
These can be marked in different ways but are normally along the lines of
L1 L2 Comm or L1 L2 L3
You state Load Slave & Live (must be a foreign switch)
You could try the following..(TURN OFF POWER)
connect cable1 yellow to LIVE
connect cable 1 red and cable2 red to LOAD
connect cable 1 blue and cable2 black to SLAVE
Try the switch & the 2 way operation with the switch at the other side of
Failing this FYI the red/black cable 2 is the switch wire from the light
(hopefully) to check this just short them together and apply power and the
light will come on permanently.
The 3core cable 2 is the strapper cable to the other switch.
The way the system works is simple ;; the 3 wires of cable 2 join the 2
switches L1-L1 L2-L2 L3-L3 or more commonly COM L1 L2.
Each colour going to the same pin on each of the 2 switches.
The switch wire from the light (cable 1) now connects (1 wire in L2 & the
other in L3) along with the blue & black from cable 2.
To simplify identification if you look at the rear of the old switch
the cable connections form a triangle IE 1 top centre
& 2 bottom left & right.
The one at the top centre is the Comm or L1 terminal and switches between
the bottom 2 terminals L1 & L2. (L2 L3)
Many thanks for the reply. This is the switch that I have purchased (there
is a PDF file showing instructions and labelling):
Although the switch says that it is 1-way it says you are abot to use it
with 2-way if used with a Slave Unit - needless to say I don't know what a
Slave Unit is :)
I have had a look and cant find the 2-way Single gang option so I assume I
will have to get a Slave Unit and fit it.
Many thanks again for your help Jon.
Yes you have a touch switch dimmer; whilst one does exist (or did last year
when I fitted 1) that is 2 way most are 1 way and use a SLAVE switch to
achieve 2way operation.
This is done electronically rather than mechanically so your second switch
The good news is that you can still use your existing wiring for the slave
For now just wire your cable 2 Red/Black into the new dimmer;
Red to LIVE and Black to LOAD do not connect cable 1 or anything to the
This will allow the switch to work but your second switch will not.
When you get the slave switch then use the cable 2 (red/yellow/blue) to
connect it as per the instructions supplied..
On Wed, 19 Apr 2006 22:10:35 +0100, in free.uk.diy.home "Marvin
TLC sell a slave unit, but you need to check if they are compatible with
your screwfix master
A diagram of the standard 2-way switching, which you seem to have, is
described in the FAQ
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