Hello

Can anyone help me wire a light switch in my loft? We've been without
light in there for about 6 years! It's our bedroom.

The thing is, there are three cables.

Cable 1 has 2 x red wires, and 1 earth
Cable 2 has 1 red, 1 black and 1 earth
Cable 3 has 1 red, 1 black and 1 earth

All three earths are joined together, as are cable 2 and 3's black
wires.

The switch was working fine until we had to pull the loft walls down,
and unfortunately we didn't make a note of what came from where. I
can't even remember if it's a two way switch working the landing light.
(The landing switch is a two way, one working the loft light).

Please, can anyone help me??

sandydog wrote:
Hello

Can anyone help me wire a light switch in my loft? We've been without
light in there for about 6 years! It's our bedroom.

The thing is, there are three cables.

Cable 1 has 2 x red wires, and 1 earth
Cable 2 has 1 red, 1 black and 1 earth
Cable 3 has 1 red, 1 black and 1 earth

All three earths are joined together, as are cable 2 and 3's black
wires.

The switch was working fine until we had to pull the loft walls down,
and unfortunately we didn't make a note of what came from where. I
can't even remember if it's a two way switch working the landing light.
(The landing switch is a two way, one working the loft light).

Please, can anyone help me??

Any idea which of these wires goes to the light fitting? Get a
electrical screwdriver (one that lights up on mains) and carefully
check which of the reds are live. I suspect cable 1 is the switch cable
and cable 2 or 3 will be power and the other the light feed.. If thats
the case then cable 1 would connect to the two red wires together when
switched. However I could be wrong so perhaps better to get a qualified
electrician in.

In article . com,
sandydog wrote:
Can anyone help me wire a light switch in my loft? We've been without
light in there for about 6 years! It's our bedroom.

The thing is, there are three cables.

Cable 1 has 2 x red wires, and 1 earth
Cable 2 has 1 red, 1 black and 1 earth
Cable 3 has 1 red, 1 black and 1 earth

All three earths are joined together, as are cable 2 and 3's black
wires.

The switch was working fine until we had to pull the loft walls down,
and unfortunately we didn't make a note of what came from where. I
can't even remember if it's a two way switch working the landing light.
(The landing switch is a two way, one working the loft light).

Where are these cables? Are they all inside the two *gang* (not way -
although it will probably be a two gang two way) switch?

Or are they the cables at the light fitting?

--
*Young at heart -- slightly older in other places

Dave Plowman London SW
To e-mail, change noise into sound.

The cables were all inside the light switch. They are now sticking out
of the wall, waiting for me to fit a new one. I've fitted a new
light, and didn't find anything unusual about fitting it. (it was a
while ago!)

sandydog wrote:

Can anyone help me wire a light switch in my loft? We've been without
light in there for about 6 years! It's our bedroom.

The thing is, there are three cables.

Cable 1 has 2 x red wires, and 1 earth
Cable 2 has 1 red, 1 black and 1 earth
Cable 3 has 1 red, 1 black and 1 earth

All three earths are joined together, as are cable 2 and 3's black
wires.

The switch was working fine until we had to pull the loft walls down,
and unfortunately we didn't make a note of what came from where. I
can't even remember if it's a two way switch working the landing light.
(The landing switch is a two way, one working the loft light).

Please, can anyone help me??

OK, deal with the two red wires first - chances are they are the live in
from the ceiling rose, and the live return to the pendant. If you have a
multimeter you could check this. With the power on[1], one would be live
and the other not. If you measure the voltage between them, you would
expect to see 240V with the bulb in, and less with it out.

The other wires will be used for the two way switching. However it is
now a bit more complicated since you only need three wires between the
switches for this to work (you probably have four!) (so it is also more
comon to use a bit of three core and earth for this wire instead of two
separate cables). Have a look at the connected switch downstairs and see
which wires go to the "com" terminal, that ought to at least tell you
the colour of the one to take to com on the missing switch. You may find
they have for example take both blacks to the com downstairs and used
one of the lives from each for the L1 and L2 connections.

Report back on what you find in the downstairs switch and we can give
you a bit more information.

[1] You need a multimeter for these tests, and you need to be confident
working with mains voltage. If in doubt seek help!

--
Cheers,

John.

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| Internode Ltd - http://www.internode.co.uk |
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Thanks everyone for your super quick replies.

John, I've had a look at the switch downstairs (which also has 3 cables
running into it.) This switch has a connector in it with 6 holes
(sorry about the terminology!) There are 2 commons. Both of these
have a red, but the bottom one has a loop of red (independant of
cables) going from the common to the 1 way switch hole in the centre,
which has a blue wire going into it. By the way, one of the cables has
a yellow wire - no blacks in sight.

Unfortunately I don't own a multimeter, but I don't mind working with
electricity. (turn the mains off, and when I turn it back on, switch
the light on with a broomstick! ha ha)

Thanks for your help!

sandydog wrote:

John, I've had a look at the switch downstairs (which also has 3 cables
running into it.) This switch has a connector in it with 6 holes
(sorry about the terminology!) There are 2 commons. Both of these

OK - that is a two gang, two way switch - i.e. two separate two switches
built into one face plate. One no doubt for the light in the room, and
the other for the light upstairs.

have a red, but the bottom one has a loop of red (independant of
cables) going from the common to the 1 way switch hole in the centre,
which has a blue wire going into it. By the way, one of the cables has
a yellow wire - no blacks in sight.

One of the cables sounds like a three core and earth (that will be the
one with red, yellow, and blue wires). Normally you would just run this
to the other switch - but something different has been done here.

Have a look at the diagrams he

http://www.diydoctor.org.uk/projects...d_switches.htm

It might be worht looking at the connections at the light fitting
upstairs in the loft to see if that is where the three core and earth
has been taken.

Unfortunately I don't own a multimeter, but I don't mind working with

Might be worth picking up a cheap £5 jobbie from a local Maplin, they
often come in useful for lots of things.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/