adding power to a shed

[bbqboy]

Hi all. I'm hoping you can help. I'm trying to run some power to me shed and I need to know the best way given my current set up. So here goes...

I have 6mm SWA cable fed by a 32A mcb from my CU in my main house. This leads to a cabin in my garden about 150 feet away. In the cabin I have a small CU using a 16A mcb and 6A mcb for sockets and lighting. I have 2 x 40W lights + a 60W light and ceiling fan. I also have a small fridge, small freezer, small stereo - not really used - and a TV. Oh yeah in total I have 6 double sockets + an outdoor socket + a 150W PIR security light that is run off a spur of one of the sockets connected to a switched FCU. Finally I have a spare 16A MCB and a 6A MCB in the CU in the cabin. That's it for the cabin.

Now about 2-3 meters from the CU in the cabin is a small shed about 12 x 14. I want to run some power to it. Basically I want 2 x double sockets + 1 hanging tube light + 1 small security light (i might get a solar one so we can drop it from the equation if it's too much hassle.

So basically I was planning to run a length of SWA cable from the spare 16A MCB in the cabin CU to an FCU in the shed. From the FCU I was going to add the two sockets and a junction box to which I could connect a switch and the light.

Is this a doable and a safe if not all that elegant way of sorting it? Your help is much appreciated. Thanks.

 

[ban-all-sheds]

• //www.diynot.com/wiki/electrics:part-p
  
  
• http://www.tlc-direct.co.uk/Book/7.13.1.htm
  
  
• //www.diynot.com/wiki/electrics:mcbtocable
  
  
• http://www.tlc-direct.co.uk/Book/4.3.1.htm
  
  
• http://web.archive.org/web/20080213151445/http://www.kevinboone.com/cableselection_web.pdf
  
  
• http://www.tlc-direct.co.uk/Book/5.3.1.htm
  
  
• http://www.tlc-direct.co.uk/Book/4.3.11.htm
  
  
• http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html
  
  
• http://www.tlc-direct.co.uk/Book/8.1.1.htm
  

 

[ericmark]

Seen a similar post on another forum! I see no reference to RCD which are required for sockets under 20A and would wonder if the LABC charges make it worth while to DIY?

 

[bbqboy]

Hi. Thanks for your reply. The CU in the cabin is fed from the RCD side of the main CU in the house. The CU in the cabin also has an RCD. I'm happy to pay for an electician, but everyone I spoke with tells me I need a special garage CU. Seems overkill to me. I may just extend the ring from my cabin to encompass the shed as the power in the shed will only be used to charge some batteries for power tools + a florry light. Although ideally I would like to keep the shed and cabin seperate if poss and I also don't want to fork out for another CU. I guess I want my cake and eat it too

 

[ericmark]

Yes I would also say overkill. Since maximum power is 16A then since:-
559.6.1.6 Lighting circuits incorporating B15. B22. E14. E27 or E40 lampholders shall be protected by an overcurrent protective device of maximum rating 16A.
Even if you did not use a florescent fitting there would be little need to fuse down. Many florescent fittings have a fuse built into the fitting so 559.6.1.6 does not apply.
The phrase "recommended by the manufacturer" comes up again and again in the regulations and the ceiling rose used in a house is rated at 5/6 amp by manufacturer so in most houses one is limited to 5 amp for lights. However this will not apply to your shed. The use of a FCU would allow the florescent fitting to be replaced without problem and using a switched FCU would be very little difference in cost to the light switch so I would use a switched FCU.
Not sure why you would have a ring in your cabin as you say 16A fuse? A radial would be more normal.
As to extending the socket supply to shed that would be no different to new circuit from 16A MCB so no point. Both need Part P so both would mean DIY cost of £100+ to LABC.
As long as RCD's are 30ma or less no point in another one.
Seems your selection of electrician was flawed or you have missed something in the telling?