Single socket in garage - spur off

[garmcqui]

Hi all,

I want to install a couple of ~60W photocell-activated outdoor lights on the wall of my garage to give some security lighting in the garden area.

The garage has it's own small consumer unit (RCD protected at the main consumer unit) with a separate circuit for lighting and for one double 13A socket.

So, I need to spur off the socket circuit... This is the current setup:

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• garmcqui
• 14 Aug 2014
• 1

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• garmcqui
• 14 Aug 2014
• 1

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• garmcqui
• 14 Aug 2014
• 1

...as you can see, there's just one t&e (presume 2.5mm?) coming from the consumer unit to the socket, so no ring main.

Can I just fit a junction box and 3A FCU where the t&e comes across the joists, or should I spur off the socket itself? (I thought you weren't supposed to spur off a socket with only one wire coming to it?)

Thanks!!

Gareth

 

[EFLImpudence]

Can I just fit a junction box and 3A FCU where the t&e comes across the joists,

A double pole 3A FCU would be best so you can use as a switch and isolate the lights.

or should I spur off the socket itself?

If you want.

(I thought you weren't supposed to spur off a socket with only one wire coming to it?)

That's correct when it is a spur from a ring.
This is a radial circuit so you can connect as many sockets as you like.

However, it must be protected by a fuse or MCB of 25A or less.

 

[garmcqui]

ok, thanks. And going from the junction box to the FCU and then on to the lights, would that have to be 2.5mm t&e or would 1mm do?

 

[EFLImpudence]

Best use 2.5 from JB to FCU

or put FCU in place of JB and have an ordinary light switch wherever you want.

 

[AndyPRK]

Why don't you connect the new lights to the light circuit ?
Or is that too long a cable run?

 

[garmcqui]

I thought about tapping into the lighting cable (which also runs along the joists nearby), but that will only be live when the garage light switch is on. I'd imagine I'd need to run single core cable to get a live all the way to the switch at the front of the garage, and another to the ceiling rose to get a neutral. Seems like more bother...

or put FCU in place of JB and have an ordinary light switch wherever you want.

How does that work, use a fused spur instead of a junction box? Why would I need another light switch? (ie: why not just used a switched FCU?)

 

[AndyPRK]

You either run a cable from the garage cu or wherever the lighting cable from the cu goes to.

There is no need to take one from one and one from another, but yes you do need a permeant live

 

[EFLImpudence]

Why would I need another light switch? (ie: why not just used a switched FCU?)

I thought the FCU (at JB position) would be too high or inconvenient.

 

[garmcqui]

You either run a cable from the garage cu or wherever the lighting cable from the cu goes to.

There is no need to take one from one and one from another, but yes you do need a permeant live

See I didn't think I was able to run a cable from the CU, I thought that made the work notifiable?


I know a 5A junction box would be ok taking a feed from the lighting circuit, but if I was to take the feed off the socket circuit, what amperage rating of junction box would I need? 30A?

 

[AndyPRK]

Yes a 30A junction box will suit the socket circuit conductor sizes

 

[garmcqui]

well I ended up just taking a feed from the lighting circuit...and it works!

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• garmcqui
• 15 Aug 2014
• 2

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• garmcqui
• 15 Aug 2014
• 2

I know it's not the tidiest, but I just want to make sure everything's ok with the wiring in the junction box... going from right to left is the main feed from CU to switch, and the "spur" is the one going upwards...

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• garmcqui
• 15 Aug 2014
• 2

 

[AndyPRK]

Well done for using the light circuit.

Junction box is tidy for a diy effort.

Did u fit a switch. ?

 

[garmcqui]

no switch yet, that's tomorrow's job (and the other light)

Can I just fit an ordinary light switch and connect both lights to that, rather than another junction box?

 

[AndyPRK]

Yes use a normal light switch and use that as a junction box.

You will need to join the neutrals in a choc block.
And earths in an earth terminal if there is one b

 

[garmcqui]

Great, thanks!