Can I put 3 conductors into the load of a DP switch?

[Sard]

Hi,

I have a dedicated garden lighting circuit in my house and I am adding 3 new lighting clusters (35w lights, with 5 or 10w GU10 bulbs, total of 18 across 3 clusters). I would like to power all three clusters from single 20A DP switch so I can isolate these clusters in the case of faults (1 supply conductor + 3 load conductors). So in essence I'm combining a DP switch with the features of a junction box but without physically fitting one.

I'd be very grateful for some advice on whether this approach is sound or alternatives I could consider?

 

[blup]

Dont see whynot, you have tne features of an FCU without the fuse. Presumably the circuit is rcd protected.

 

[Sard]

yes, it's RCD protected at the CU.

 

[AndyPRK]

depending what size cable you are using, you will may need a deep back box.

It's not 3 SWA is it?

 

[Sard]

depending what size cable you are using, you will may need a deep back box.

It's not 3 SWA is it?

No, 2.5mm T&E for each conductor as this sits inside my garage. Two clusters are fence mounted so I'll be using .75mm flex to loop in and out. The 3rd cluster is in flower beds, so one 2.5mm T&E will connect to a weatherproof jb mounted on an exterior wall, from which an SWA cable will be buried underground to another JB attached to the flower bed. From there I'll run .75mm flex to loop in and out from each ground spike light.

I hope that makes sense? If not, I'll try to clarify.

 

[AndyPRK]

4 lots of 2.5mm in the box then,
If using a metal back box, I think you would need a 35mm minimum

2.5mm is very big for lighting! If you wanted an outside socket, then I could understand why one would be 2.5mm

1.0mm usually used for lighting.

You could use 1.5mm as a compromise if you want to fit a socket

Your just making your life more difficult trying to get 4 x 2.5mm into a single box, then even pro's wouldn't want to do.
Better to use smaller cable or have a separate junction.

 

[Sard]

4 lots of 2.5mm in the box then,
If using a metal back box, I think you would need a 35mm minimum

2.5mm is very big for lighting! If you wanted an outside socket, then I could understand why one would be 2.5mm

1.0mm usually used for lighting.

You could use 1.5mm as a compromise if you want to fit a socket

Your just making your life more difficult trying to get 4 x 2.5mm into a single box, then even pro's wouldn't want to do.
Better to use smaller cable or have a separate junction.

Thanks Andy. I'll have a go and see how I get on. I'll also consider dropping down to 1.5mm2 as you're 100% right.

 

[AndyPRK]

If its just some lights, then a 13A FCU would be more suitable to protect the 1.0 or 1.5mm cable. (fit a smaller fuse if only lights). Depends what's protecting at the source

 

[Sard]

In the past I got advice from the forum that a 20a DP switch would suitable to safely isolate external lights as the circuit is protected by an RCD at the CU. Would this negate the need for an 13a FCU? If not, I can fit that instead.

 

[AndyPRK]

It's an excellent idea having dual pole isolation when running cables outside. A 20A switch or 13A FCU should both do this.
Can turn it off then if you get water into the outdoor electrics

This one says DP in the title (dual pole), so would be ok

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[Taylortwocities]

This one says DP in the title (dual pole), so would be ok

I don't remember seeing a switched fused spur that was anything but double pole.
PS. Don't buy kit from anyone who has spelling errors in the product title. It shows a lack of care which may be reflected in product, service, etc.

 

[Sard]

Thank you folks, I'll go with a 13a FCU Much appreciated!