Grid RCD?

[phatboy]

Hi all,

I have a bit of an issue planning the wiring for my new outside lights.

We are going to use some low voltage LED lights in the garden, on 2 circuits.

There is currently a switch for the 1 outside light, and I want to replace this with a 2gang switch. This switch is on the downstairs lighting circuit, which is not RCD protected.

We have a 12 year old MK CU that is full, and the RCBO's for it take up 2 spaces, so we cannot convert the lighting circuit to use an RCBO.

So my proposed solution is to turn the single backbox in the wall for the outside light into a double, fit 2x dual pole switches in a grid plate, and fit an RCD in the grid if such a thing exists. So far I cannot find one.

Can anyone suggest where to find one, or some other genius solution?

Thanks

 

[PrenticeBoyofDerry]

Have you thought of an RCD protected spur?

 

[Chri5]

3amp fuse spur with an rcd before the switch? You can get fused spur rcd units.

Mid term it would be worth think about an update to the board and bonding. Rcd's do a important job.

 

[PrenticeBoyofDerry]

Also has the switch got a neutral?

 

[phatboy]

3amp fuse spur with an rcd before the switch? You can get fused spur rcd units.

Mid term it would be worth think about an update to the board and bonding. Rcd's do a important job.

Thanks, I want to avoid having to install too many backboxes - the walls are block and the room has recently been decorated!

When I moved in a few months ago I added some additional RCBO's to the board, so that all the socket circuits were protected (the kitchen and downstairs already were).

I would like to use the position of the existing switch for the outside lights, as its very convenient.

Do you think a grid RCD does not exist?

Thanks
Tim

 

[phatboy]

Also has the switch got a neutral?

Yes there is a neutral in the box

 

[Chri5]

No grid rcd exists, could you run a spur from the rcd protected socket circuit up to the existing switch?

Then grid switches and a fuse spur grid, so you'd need 3- w grid plate / double back box ?

 

[phatboy]

Shame!

Running a spur from a socket would be ideal, but of course there is no socket in the area around the switch, there is one on the opposite side of the doors.

Your solution is still a possibility, it would just mean I have to have the switches on the other side of the door. I could in fact replace the double socket that is there with 2 switches and a fuse in a grid plate, then just drill a hole out the back of the box to outside.

Its not exactly what I wanted, but without tearing up the house its the best option!

Thanks
Tim

 

[PrenticeBoyofDerry]

Are the cables accessible for the lighting circuit at the fuse box, an alternative would be to introduce an external RCD module to the circuit at the CU.
But this would then mean all downstairs lights are protected by shame RCD as the outside lights, so if a residual fault then occurs outside, it will take your whole downstairs circuit out.

 

[phatboy]

Are the cables accessible for the lighting circuit at the fuse box, an alternative would be to introduce an external RCD module to the circuit at the CU.
But this would then mean all downstairs lights are protected by shame RCD as the outside lights, so if a residual fault then occurs outside, it will take your whole downstairs circuit out.

Its possible, but not a solution I would espeically like to be honest!

If I was to go down that route I would be using DP switches for the outdoor lights anyway, so could easily isolate then in case of a fault.

 

[plugwash]

Thanks, I want to avoid having to install too many backboxes - the walls are block and the room has recently been decorated!

You do know you can get backboxes that take two single sized accessories right.

http://www.screwfix.com/p/appleby-galvanised-steel-dual-35mm/48234

 

[phatboy]

Thanks, I want to avoid having to install too many backboxes - the walls are block and the room has recently been decorated!

You do know you can get backboxes that take two single sized accessories right.

http://www.screwfix.com/p/appleby-galvanised-steel-dual-35mm/48234[/QUOTE]

Hi,

Yes thanks I have used a couple of them before for bathroom light and fans.

Although as they are wider than a double backbox, I'd still have to hammer drill my nicely painted walls! If I am lucky it would be quite easy and require minimal repair. Although it may end up making a nice crack up the wall!

Tim

 

[sparkwright]

Just do what Prentice Boy says and fit an in-line RCD in an enclosure next to the cu, so it serves the whole lighting circuit in question. New lighting circuits are nearly always wired now with an RCD protecting it completely. Or find an RCBO that does take up only one way in the board.

You may need the RCD to protect any new cables that may be just below the plaster surface.

The double pole grid switches will stop the circuit tripping if there is a persistant fault on the outside lights.

 

[vibrobullit407]

Can you change a dual module RCBO for 2 single module RCBO's in the cu? Not a cheap option and maybe difficult to fit in the not as tall wylex boards but could still be an option.

 

[securespark]

Are the cables accessible for the lighting circuit at the fuse box, an alternative would be to introduce an external RCD module to the circuit at the CU.
But this would then mean all downstairs lights are protected by shame RCD as the outside lights, so if a residual fault then occurs outside, it will take your whole downstairs circuit out.

That's what would happen if the GF lighting was protected by RCBO, so I can't see a problem with that.