convert switch to two way

[itsajungleoutthere1]

in my living room i have two lights that are switched independantly from a two gang two way switch but only used as one way.
i would like to convert this to two way as i have done in my kitchen/diner,but the cabling is different.
so i have a two gang two way switch with the following
on the top row L1-red cable linked to L1 on bottom row
on the top row L3 no cable
on the top row L2 yellow cable with red band
on bottom row L1-red cable linked to L1 on top row
on bottom row L2 blue cable with red band
on bottom row L3 no cable,
What is required to convert to two way
any help would be appreciated.

 

[333rocky333]

you would need to run a three core and earth cable from the existing switch to your new switch.

If you want both existing to become two way then you would need to run Two 3c and e cables

 

[Spark123]

If you look at the back of the switch you'll find the switch are arranged in a triangle fashion i.e you'll have an L1, L2 and L3 for each independent switch.
All you need to do is fit a strapper between this switch (using 3c&e) and the new switch.
The wire in L1 of the original switch then goes into L3, the strapper links L1-L1, L2-L2, L3-L3, earth to earth. (unless your new switch has COM, L1 and L2 which are the same as COM=L1, L1=L2 and L2=L3).
Here's some additional info:
//www.diynot.com/wiki/electrics:two-way-lighting
You should also sleeve all lives brown in the switch for good measure and place a notice at the consumer unit that colours to two versions of BS7671 are used.
If the switch is going to be in the kitchen then the work will be notifiable to your LABC under part p of the building regs. If it is in the lounge then it is non-notifiable.

 

[itsajungleoutthere1]

Thankyou for the quick replies,

I understand where you are both coming from,this is what i was expecting to be doing.
the issue i have, i was expecting to see 2 x t&e cables instead i only have 3 core & earth running to the original switch
do i have to re cable to make both two way
thanks

 

[Spark123]

On the switch you want to make two way you need to have the red (permanent live) into it's L3 terminal instead of common.
If you move the one with two red wires in then you need to move both the permanent live and the link to the other switch (albeit 3 in the same terminal can be a bit crowded so a rejig so you only have two is easy enough)

 

[XtraRaptor]

Thankyou for the quick replies,

I understand where you are both coming from,this is what i was expecting to be doing.
the issue i have, i was expecting to see 2 x t&e cables instead i only have 3 core & earth running to the original switch
do i have to re cable to make both two way
thanks

The electrician who wired the switch used the 3c & E as you only need a live and 2 switch wires down to the switches, then there will be a link between the common connections on each switch.

 

[sparkwright]

Thankyou for the quick replies,

I understand where you are both coming from,this is what i was expecting to be doing.
the issue i have, i was expecting to see 2 x t&e cables instead i only have 3 core & earth running to the original switch
do i have to re cable to make both two way
thanks

The electrician who wired the switch used the 3c & E as you only need a live and 2 switch wires down to the switches, then there will be a link between the common connections on each switch.

Quite. Perfectly normal and correct. No need to change.

OP, imagine the red you have is the two reds you were expecting see, only linked.
Imagine the yellow to be one of the blacks you were expecting.
Imagine the blue to be the other black you expected.

The red is permanent live, the others are separate switch lives.

And remember how the back of a 2 gang switch is formed; there's an almost vertical line dividing the back into two entirely separate switches.
Forget all that rubbish about top row and bottom row - that's not the way to establish how it's wired.

 

[sparkwright]

Switch markings can vary from make to make.

L1 L2 L3 suggests Crabtree.

Usual markings are Com, L1, L2.

L1 = com
L2 = L1
L3 = L2

 

[ericmark]

In the UK we wire two way switching like this

but in school we were shown how to wire like this

the problem with latter is one would need a junction in the switch back box. Works great at school but not much good in a house where we use cables rather than wires.
There is an odd method used some times like this

but rare.
So the normal is to wire lights something like this

I hope now you can see what is being done it will become easy. Basic with two way wiring the strapper joins like to like.

 

[itsajungleoutthere1]

Thank you to all for your help,all sorted