electrical advice please....

Reality Bites · 7 Oct 2013 at 10:06

I need some help tidying up a switch setup. We have just had our bathroom re-fitted. The single light was replaced with 4 spots which run off the same ring the old one did. The pull string switch has been replaced with a single switch outside the room (it's a small ensuite so no biggy).

We have also had some small LED's put in the wall of the shower. These are 12v and run off a switched fused spur.

My problem is i hate the fact i have two single box switches. I asked if the two could be replaced with a single box, double switch setup but it seems it can't. (Not had the official reason yet but will post back when i do, i suspect it's down to different voltages maybe?).

Is there anyway i can reduce the two switch boxes to one. I don't mind if it's all on the same switch but really want a single switch box solution.

any advice appreciated!

Dava · 7 Oct 2013 at 12:23

i can't see why not, although the transformer might be in the back of the switch faceplate for the 12vdc, should be able to get a faceplate that you can put 2 switches in 1 being the normal switch the other being a switch with the 12vdc transformer on ( they just click in), have a look at RS components or Farnells for something. (there are cheaper places but if these should stock them)

BigBoy · 7 Oct 2013 at 17:50

Its because the LED's are fused they have to have there own switch, I had a similar problem in my kitchen!

C.R.A.Z.Y · 8 Oct 2013 at 22:11

You have been lied to.

1 x 2-gang switch is electrically no different than 2 x 1-gang switches.

BigBoy said:
Its because the LED's are fused they have to have there own switch, I had a similar problem in my kitchen!

You have not read his question properly, he still wants them switched individually however he wants to do this with a single 2-gang switch rather than 2 x 1-gang switches.
That said I still don't agree with what you are saying, providing the switch current rating is sufficient then electrically their is no reason why a single gang switch can't isolate more than one 12v lighting transformer.

ZG002 · 8 Oct 2013 at 22:37

C.R.A.Z.Y said:
You have been lied to.

1 x 2-gang switch is electrically no different than 2 x 1-gang switches.

You have not read his question properly, he still wants them switched individually however he wants to do this with a single 2-gang switch rather than 2 x 1-gang switches.
That said I still don't agree with what you are saying, providing the switch current rating is sufficient then electrically their is no reason why a single gang switch can't isolate more than one 12v lighting transformer.

You have not read the question correctly I'm afraid. The op currently has a 1 gang switch for his spots and a switched fused spur for the L.E.D's. Not 2 x 1-gang switches.

I'm guessing the L.E.D's specify they need to be fused down to something like 3amp while your lighting circuit will be protected by a 6amp mcb or the like. Only reason I can think of them needing to be ran through a fused spur.

C.R.A.Z.Y · 8 Oct 2013 at 23:00

Yeah my bad I've totally not read it clearly.
However there is no reason other than the sparky being pedantic why these two circuits can't be switched in one box using a single 2-gang switch (obviously the two switches are totally independent of one another)

Why would the LED's need fusing down to 3A ???
The MCB/RCBO/re-wireable fuse's Amperage rating is simply there to protect the cables from demanding more current then they can safely carry.

The 12V lights should be switched using the 240V supply to their transformers and not the 12v output. (personally I'd not bother with 12v lights and instead use 240V Gu10, using transformers just introduces a non-user accessible component that will fail and need replacing at some point)

Provided the radial is RCD or RCBO protected then there is no reason from a safety point of view that the O.P cannot have them switched in a single box using a 2-gang switch.

/16th Ed.

**EDIT**
Maybe the reason for the fused spur is because the 12v Transformers have the supply cables hard wired and they are <1.0mm CSA, however it's still pretty lame as someone who doesn't understand electrics might replace the blown fuse with a 5 or 13 Amp fuse!!!
That would then totally remove the purpose of the fused-spur in the first place and the <1.00mm cable is no longer protected for current overload ?!?!? (Unless of course the spur is of a type that will ONLY except non-standard plug-fuse's that do not go above 3 Amps?!?

Whatever the case they really have made it far more complicated than it needed to be

HardwareGeek · 8 Oct 2013 at 23:59

Need to check manufacturers instructions to see if they do need fusing down to 3A, but would be an annoying design seeing they would be run off 5/6 maybe even 10A lighting circuit.

Maybe instructions just say it needs an isolation point but doesn't need fusing down?

Also no reason except laziness why even if fused down it cant still be switched from a 2 gang just need to run an extra cable to the switch

Or run them off a PIR, then you can use them as a night light when peeing in the night? then you wont get fully woken up by the harsh main lights?

ZG002 · 9 Oct 2013 at 07:40

C.R.A.Z.Y said:
Snip

I agree with you, I was just pointing out the possible reason, as if the electrician thought he could just use a 2G switch he would have as it's easier for him to just run both circuits to the one back box.

Of course he could have done as HardwareGeek says and just put a un switched spur in place somewhere and still switched from a 2G. Which is what I'd mention op if he kicks up a fuss.

What's with signing off /16th Ed?

Reality Bites · 9 Oct 2013 at 08:35

i believe the fused spur was needed as the tiny LED's in the shower basically came with a plug on. They were one's designed for internal or external use. I was wondering if swapping the switched spur for a none switched and then running it to the light switch would work, but i don't know enough about electrics to argue.

We have removed the extractor fan from the ensuite and the LED's run off that circuit. in my simplistic mind though, i can't understand why a non switch spur can't be controlled from a light switch?

Reality Bites · 9 Oct 2013 at 08:38

HardwareGeek said:
Need to check manufacturers instructions to see if they do need fusing down to 3A, but would be an annoying design seeing they would be run off 5/6 maybe even 10A lighting circuit.

Maybe instructions just say it needs an isolation point but doesn't need fusing down?

Also no reason except laziness why even if fused down it cant still be switched from a 2 gang just need to run an extra cable to the switch

Or run them off a PIR, then you can use them as a night light when peeing in the night? then you wont get fully woken up by the harsh main lights?

He did try running a cable from the spur to the switch (that's how it was going to be configured) but it kept blowing the breaker. I'm going to consult another sparky in the next couple of days.

I had considered a Timed PIR device.....do they act as a little breaker? They would only come on when we were in the room then....perfect.

ZG002 · 9 Oct 2013 at 10:04

You could just replace the switched spur for a un-switched spur and run your load side through a switch or a 3 core to a pir. A pir is just a switch activaed by movement, they are becoming fairly popular in bathrooms for use with things like led's used as night lights as Hardware says.