extending my light switch?

[KRB78]

Hi, whats the best practice for extending a light switch?.
At the moment i have one dimmer switch in the front room but its well away from the main door and hard to keep getting too, so my thoughts were to extend the wire from were it is now to its new location and put a new switch in there instead.....sounds simple but is it?

kev

 

[Spark123]

It depends on the wiring method, if it is a loop in at the rose system then pulling a new cable in from the rose to the new position is the best way imo.

 

[Taylortwocities]

When you run the new wiring in, what will happen to the old switch?

Can you post a photo of the connections at the back of the existing switch.

 

[KRB78]

i will take a pic of the back of the switch today...and i was going to leave a blanking plate on the old switch.

spark123...not sure about the rose conections and access is very limited ...

thanks for the replys tho guys

 

[Taylortwocities]

Depending on the connections you may be able to have a new switch and keep the old one - so you can switch on and off at either.

Lets see the pix and we can see what is going on.

 

[CWESPARK]

A couple of thoughts,

Have you considered how you will physically install the cabling to the new switch position? Are you going to chop it into the plaster, sheath it over and re-plaster it? If so you may as well do away with the old switch box completely rather than blanking it off, just remove the backbox and plaster it up. This will of course depend on how you join the cable, or if you run a new one in.

Can you get access to the cable route, IE is there a loft above, or can you lift the floorboards to get to the cable between the ceiling rose and the switch drop? If so you may be suprised, a simple re-route may give you enough cable to re-use the existing cable to your new switch position.

Yes, get some pictures up so we can have a proper look.

Cheers,
CW.

 

[sparkwright]

Would it be handy to keep the old switch position as well as having a new switch position?

Perhaps there are two doorways; you speak of the 'main door'.

You could, if that is the case, fit 1 gang 2 way switches.

You would have to run a 1.0 or 1.5 mm2 3 core and earth flat cable between the switches.

 

[ban-all-sheds]

Have you considered how you will physically install the cabling to the new switch position? Are you going to chop it into the plaster, sheath it over and re-plaster it? If so you may as well do away with the old switch box completely rather than blanking it off, just remove the backbox and plaster it up. This will of course depend on how you join the cable, or if you run a new one in.

He's almost certainly talking about moving it horizontally, in which case no matter how he joins the cable he can't not have the blanking plate there.

 

[KRB78]

the job has been put on hold while me dad decides if he really wants me to change it......

i will continue on here if and when he gives the go ahead.

thanks for the replys tho.

 

[KRB78]

ok, here are the pics i promised ...thought id get some info while i waited...

this is the wall in question with a dimmer switch one end (although this can be changed back to a normal switch if need be)...and i would like to put another one the the right at the other main doorway.

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• KRB78
• 24 Apr 2011
• 1

on the back of the light switch/dimmer is 3 connections with one saying L1 and the other L2 ...not sure what the other says.

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• KRB78
• 24 Apr 2011
• 1

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• KRB78
• 24 Apr 2011
• 1

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• KRB78
• 24 Apr 2011
• 1

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• KRB78
• 24 Apr 2011
• 1

hope this helps, can i keep the switch and run some new cable through new duct work to the new switch on the right hand side of the wall?

thanks-kev.

 

[securespark]

I would keep the existing switch and extend horizontally to another. Unless you use special dimmers, you can only have one at one end or the other, not both.

 

[KRB78]

so i could have a dimmer on the right side and a normal switch on the left?..or normal switches ob both sides?

I have flat 3 core wire with earth, how do i wire the switches up?

 

[sparkwright]

By having two 2 way switches it will be more convenient for the user, also saves problems with concealed joints and cables zones.

You can chase across horizontally. You can also go up or down if you prefer, if the cable will be run under floorboards.

Basically, the cable needs to be in a straight run in line with the switches.

You can have one dimmer at one end or the other. You cannot have two (ordinary) dimmers. You can have two ordinary switches.

The switches you require are known as 1 gang 2 way. They have one switch, and three terminals on the back.

The dimmer will usually require a 25 mm deep back box.

Use grommets where the cable enters the back box, earth sleeving on bare earth wires. Oval conduit or capping is desirable and recommended over the cable if you are chasing it in. It's not expensive.

For wiring, choose a colour to use as common on the 3 core and earth cable. For the sake of argument, lets say brown is the common, black is L1, and grey is L2.

At existing switch
Connect new brown to common
New black and old red to L1
New grey and old black to L2

At new switch
Connect new brown to common
New black to L1
New grey to L2

By rights, all these these wires should be sleeved red/brown to indicate they are live wires.

Switch markings can vary according to which manufacturer.
Com
L1
L2
is usual

Crabtree, for instance, use
Com = L1
L1 = L2
L2 = L3

Work safely, and if in doubt ask for help first.

Look up safe zones for cables.

 

[bernardgreen]

For wiring, choose a colour to use as common on the 3 core and earth cable. For the sake of argument, lets say brown is the common, black is L1, and grey is L2.

Or use black for L2 and brown for L1 and grey for common


then at the existing switch

Connect new brown to common
New brown and old red to L1
New black and old black to L2
New grey to common

New black to old black is less confusing than black to red with brown (or red) sleeving.

At new switch
Connect new grey to common
New brown to L1
New black to L2

That is how I would do it, browns and reds are live ( phase ), blacks are all black ( switched live ) and grey is strapper live.

 

[sparkwright]

As we all know here there are no rules about which colours to use on a 3 core 2 way cable; any colour may be used for the common or the strappers, providing they are sleeved appropriately.

There is no reason why you shouldn't join an old unharmonised black to a new harmonised black. It would indeed be less confusing for the op and anyone else.

However, I do not recognise that black in a old unharmonised cable would automatically match up with the black of a new harmonised cable. The old colours are one system, the harmonised another.

Again, absolutely no reason why you shouldn't join the blacks together, and I agree there is some logic to that.