Wiring Advice for 2G 2W light Switch

[studentspark]

View media item 21579
I find it hard to follow what is going on at a switch without testing for live and switch live

Right hand side is a two way switch with strappers

Yellow in com will com to com in other switch
blue in L2 will go to L2 in other switch where there will be a switch live

red in L1 will be perm live which will go to L1 in other switch also with perm live

red in L1 linked to other switch to provide perm live.


This is where I get a bit confused

now the left hand side

the red in L1 will come live when the switch is on

the black in L2 will come live when the switch is off

wont that light always be on

 

[davelx]

You need to know what is at the other end of the cable from the left side. For example, if that switch is in the hall, it's likely that the left switch is also two-way controlling the landing lights with the neutral tapped off another upstairs light. In other words the red & black are strappers too.

Very common in houses with only a single lighting circuit, and a recipe for a borrowed neutral if a new CU is fitted with separate lighting circuits for each floor.!

 

[1john]

i suspect the link will go from one C on one switch to the C on the 2nd switch.

#

no it won't ...

the link goes from the red in the 3 core and earth which is in the L1 ( or L2 ) terminal of one switch, to the common of the other..

your existing switch is 2 triangles, one upside down to the other.. ( as can be seen by the diagonal line on the back of the switch.. )

the yellow goes in one com, the blue from the same cable to L2, the red form the same cable to L1 ( and linked to the other com )
then your other cables go in L1 and L2 of the other switch..

and don't forget a link from the earth in the backbox to the switch plate itself..

perhaps i posted that before there was any pictures

 

[ColJack]

don't fib..
the pictures are on the OP and there is no note to say it was edited so thy must have been there before you posted your reply..

 

[sparkwright]

View media item 21579
I find it hard to follow what is going on at a switch without testing for live and switch live

Right hand side is a two way switch with strappers

Yellow in com will com to com in other switch
blue in L2 will go to L2 in other switch where there will be a switch live

red in L1 will be perm live which will go to L1 in other switch also with perm live

red in L1 linked to other switch to provide perm live.


This is where I get a bit confused

now the left hand side

the red in L1 will come live when the switch is on

the black in L2 will come live when the switch is off

wont that light always be on

STUDENTSPARK,
If you study the right hand switch, somewhere further along will be another 2 way switch. Now either at this other switch, or at a jb, or at the rose; the blue will be connected to the sw live, the red to the perm live.
The easiest way to imagine this would be to think of a conventional master 2 way switch; where you have a 2 core in red and black which is this switch wire from a standard 3 plate rose. This red is perm live. At the switch it connects to the red of the 3 core which also then becomes perm live. This red then goes on to feed the lefthand switch in the picture.

The lefthand switch will feed another 2 way switch via the strappers. At this next switch the common terminal wire will feed the light.

You will notice at the righthand switch the perm live is at L1
and
at the lefthand switch the perm live is at COM.

Quite normal.

With two way switching there are countless ways of doing it; when it comes to re-wiring or altering wiring all these methods are used to make the job easier, usually.

 

[ban-all-sheds]

and once you remove those screws and pull the switch forward a bit to paper round it while it's still live ( we've all done it....

Not me.

1. Turn off the circuit, (safe isolation procedures malarkey).
2. Remove the switch.
3. Join conductors together with choc-block if the light will be needed before the switch can go back, alternatively make the conductors safe with c-b.
4. Protect against paste or paint with gaffer tape (yes, that's perfectly adequate unless you are pasting the wall).
5. Turn the circuit back on.
6. Paper right over the back box.
7. When dry turn off the circuit (safe isolation procedures malarkey), carefully cut around the inside of the box with a scalpel, remove square of paper, remove tape, replace switch.

 

[1john]

I can assure you they were not there, why would I post something that with pictures is clearly wrong? I am not a liar, there were no pictures on the post when i replied!

I opologise to the OP if my response caused any confusion.

 

[ban-all-sheds]

'tis obvious how it happened.

jaybee2 Posted: 14th April 2010, 23:03 Post Subject: Wiring Advice for 2G 2W light Switch

1john Posted: 14th April 2010, 23:05 Post Subject:

Jaybee added the photos after you started your reply, which is why you hadn't seen them, but before you finished it, which is why there's no evidence of an edit.

Nobody is lying, and nobody is going mad.