Splitting lighting circuit

[matt204]

Hi all, I am splitting a room into 2 rooms and need to split the lighting for the 2 individual rooms. The current room already has 2 switches (1 in either of the new rooms). So I just need to add an extra light fitment in one of the new rooms and have each switch operating each individual light.

Is this quite an eay job to do and will I need to inform building control?

Many thanks.

 

[ban-all-sheds]

Is this quite an eay job to do

It's not complex.

But it will involve changing a 2-way switching circuit to 1-way, possibly removing/changing cables, which may mean lifting floors, chopping into walls etc, so how easy you personally will find it we can't say.

and will I need to inform building control?

Not unless either room is a kitchen or bath/shower room, or you are introducing new concealed cables and want to comply with the Wiring Regulations by RCD protecting them if the circuit already isn't.

 

[dizz]

Any sparky able to tell him :

1. if he can connect another twin and earth cable to the existing ceiling rose to create another ceiling rose in the new room?

2. the size cable he needs to buy?

3. How using a multimeter would help him identify and remove the switches?

I am sure he wanted a bit more than "it's not complex"

Unfortunately Matt I am not a sparky and cannot therefore help as I may give incorrect advice.

But if I were doing the job, I would first identify the switch cables.

This post might be helpful :

//www.diynot.com/forums/viewtopic.php?t=200734

This thread is for a single (NOT two way switch - your switch will contain THREE CORE AND EARTH cables not TWIN AND EARTH - assuming the two switches you refer to operate the same ceiling rose - but the thread is helpful, because it shows you what you now want to achieve rather than what you may have with your two way switching). So I would remove all of the existing switch wires from the switch to the ceiling rose and replace with twin an earth from the switch you wish to use for the existing light and install new twin and earth cable in the other switch which will operate the new ceiling rose you will be installing.

You should only need a multimeter if you forget which wires are the switch wires after disconnecting. The ceiling rose should tell you which is the switch wires.

A sparky might be kind enough to tell you if you can use the existing three core and earth switch wires without replacing it - if it is possible.

In the picture from RF Lighting, he is using some OLD coloured cable - you might see Brown for Red and Blue for black - but it neatly shows you how a typical ceiling rose and switch is wired.

That's what you need to aim for in the existing ceiling rose and the new one you wish to install.

In respect of the new one - I would "suspect" it would be alright to "spur off" the existing ceiling rose to create a new ceiling rose by using 1mm Twin and earth cable - that is connect a new cable to the existing ceiling rose to the existing Live, Neutral and Earth, so you have an additional cable in the ceiling rose (it might get a bit busy). A sparky should confirm this.

From the new ceiling rose, you need to achieve the same set up as the picture from RF Lighting I have referred to, but this time the new ceiling rose will not be supplying an additional ceiling rose, so will contain one less wire.

The key thing for you is to identify the switch wires and main circuit wires.

Please check before doing any work.

 

[ericmark]

The cable which allows two switches to work one lamp normally goes from switch A to switch B and often but not always goes no where near the ceiling lamp so it is likely you will need access to cables which could mean lifting floor boards.

There are non standard ways to do two way switching as well as the normal method so without testing it is impossible to say exactly what is required in your house.

As to if easy or hard I find complex numbers easy and calculus very hard other students find the reverse so how can we know what you will find hard.

To me the only thing in domestic wiring which ever causes a problem is central heating wiring so I am sure I will find it easy and boring.

 

[matt204]

Thanks for the information. Hopefully I should find enough info from that previous thread. I knew I was going to have to pull floorboards so that is not a problem.

 

[333rocky333]

What cables are in the switches.

If it is a three core and earth in one switch
and
a 2core and earth as well as a 3core and earth in the other switch

You may be able to cut and reuse the 3 core and divert into each rose if it goes to the switches already.
Disconnect and safely seal off the existing 2 core from the rose to the switch,
Run a new twin and earth, possibly 1.5 mm from rose to rose, then just reterminate, to suit the new wiring at the roses and the existing switches.