Adding a spur to a radial circuit (UK)

[Integrator741]

Hi all,

I'd like to provide my shed with some power. I know that ideally I should use a spare way in my consumer unit, but I want to save some time, money and effort and so I am thinking to add a spur to "garage radial circuit". I have a plan in my head, but I want to check it with someone. Also, as far as I understand, this addition is classed as a notifiable work according to Part P building regulations am I right? So before I start any work I should contact appropriate authorities and find a competent person to supervise my work.

The garage:

Radial circuit in the garage fed from 16 Amp RCD. 2.5 mm Twin and Earth cable comes in a switch and then from switch I got another two cables going to light and double socket (T&E). So knowing that, can I come from the switch with another 2.5 mm twin and earth to Fused connection in my shed and then from fused connection to double socket and a light? Or should I go from the double socket in the garage and then to fused connection?

Many Thanks.

 

[Arouse1973]

How far is the shed from the garage?
Thanks
Adam

 

[Integrator741]

How far is the shed from the garage?
Thanks
Adam

about 10 m

 

[Arouse1973]

So as far as I am aware you can only have one spur per socket. So if the feed into your garage is not a spur then you can spur off the socket in your garage once. If you then spur off again for the light I think this would be two spurs and that's not allowed because the max spur current is 13 Amps and connecting a lighting circuit to this will potentially push it over the limit. Also the spur has to use the same rating of cable feeding the socket you are using as a spur. But you could plug an extension lead into the socket and run a light from that as this will be fused at 13 Amps. Might be worth speaking to an electrician first.
Thanks
Adam

 

[siggy]

Are you positive your on a radial circuit? I see you hale from London England and unless things have changed since I emigrated most domestic circuits are ring circuits so technically and confirm with a qualified electrician first but it should be easy to split the ring insert a rccb to protect down stream supplies.
Either that or if you have a spare breaker position run new and use a distribution box in the garage
There is a term for this second box escapes me right now but it doesn't have the main breaker used. As the main house "main breaker" will protect both

 

[Arouse1973]

I think it was quite common in the UK to use a radial circuit in garages that only had one socket for say a freezer or something. Just had a quick Google and the term radial circuit and garages pop up quite a bit. But I might be wrong.
Adam

 

[siggy]

You are correct but I got the impression the op was wanting to supply his garage from his house. Re-reading it his garage is feeding his shed

Having said that if he puts a pony panel with mccbs into the garage. 2.5mm - if possible upgrade the t&e to 4mm and breaker - supply to a breaker panel then creates a ring main in the garage and another socket and wire back to panel then from there he can spur off to the shed.

As we are all in cyberspace we can only advise on options

 

[siggy]

Get an electrician to provide a quote and a simple design
As a homeowner I believe you can still do the work and get a sparks to check it before it becomes live.