Switching two appliances from one four-core cable

[Martin Pentreath]

Many thanks to all for the electrical advice on other threads. I am aware of Part P - I am trying to get various things sorted out and cables put in before getting an electrician in to do the final stages.

Having thought a bit more about my garden wiring I would like to be able to control separately both a small fountain and some outdoor lighting from within the kitchen. I would take these off the same 13A spur from the ring - the load would be no more than 300W.

Rather than running two cables can I (for the sake of neatness and economy of cable) use four-core cable, with two separately-switched lives? The fountain and the lighting would then both share the neutral and the earth. Just need to know so that I can order some cable and put it in now.

[Set Square]

As long as the neutral can handle the current of both appliances at the same time, and as long as the single earth wire is adequate, I don't see a problem.

I did something similar with my pond wiring (pre-Part P!) - using a 7-core SWA cable for water pump, air pump, and UV filter - each seperately switchable from the house. In my case, each had its own neutral - with just the earth wire being shared.

[Christian McArdle]

Yes. No problem. Use SWA. Thickness depends on length, but at 300W, you can probably use quite thin stuff. You will need to buy some brown and blue sleeving so that the colours of the cores are correct when terminated.

Christian.

[Andrew Gabriel]

As others have said, that's fine.

However, what I would probably do in such a scenario would be to send a single permanently live feed down the garden. Tap off this through FCU and remote control switches for the fountain and lights. I would use X10 switches which carry the control signalling over the mains. This would enable you to easily add other things in the future, and you could install a regular waterpoofed 13A socket in the garden too, which I find extremely useful.

[Set Square]

Sounds interesting! Can you get X10 switches with a fair modicum of weather protection - or are they only intended for in-door use?

Any suggestions of specific kit?

[Andrew Gabriel]

I would probably look at putting one of the following modules inside the back of a weathproof socket or FCU module:

. I haven't tried this, so I can't guarantee it will fit -- probably need to take one into B&Q and see which weatherproof socket range you can get it into the back of. You can also connect a local momentary action switch to this device for local switching.

A cheaper module is

but it would not fit in the back of a socket or FCU module, and would need a dedicated weatherproof case.

Somewhere in the middle is

is DIN rail mounting -- if you require several separate remote switches, using a weatherproof DIN rail box could be a good option.

[mrcheerful]

It will work, but: If your paired neutral fails after it is paired then BOTH appliances will be live (one through the neutral side), yet neither working, surely that is not a good idea from a safety point of view.

mrcheerful

[Roly]

I did exactly that last year.

I ran one, three core SWA from a circuit breaker to a waterproof box ( from CPC ) and inside the box are three X-10 modules ( AM12W wire-in modules ) to power the outside lighting, the pond pump and a mains socket on the patio.

The whole lot is conrolled from a tiny switch module which can be plugged into any socket in the house and moved around as convenient.

I've since added an X-10 timer to automate some switch-on times and added some other plug-in units to conveniently control other stuff around the house.

I bought the X-10 stuff here -

service is excellent and they rapidly responded to my e-mails.

[meow2222]

a non issue unless for some reason you decide to connect the cases to the neutral conductor. While common enough in the US, so I hear, its not done here.

NT