Help with summer house supply

[AD23]

Hi all

I've agreed to help a relative supply power to his summer house and wanted to run my plan by you and ask for any advice you might have. I'll give you as much detail as possible - some might even be irrelevant.

-My uncle requires three double sockets in the summer house with a view to running two lamps, a laptop and printer, and on occasions a 2kw plug in heater

-The summer house is located 15metres from the back of the house

-The house is terraced meaning any supply will have to run through the house however the flooring is all parquet which my uncle is reluctant to lift

-The house currently has no RCD protection

-My plan is to spur from a socket in the back room to a 13A RCD Fused Connection Unit, go through the wall to a junction box, run 3core SWA cable (using 3rd core as a CPC) along a pre installed conduit that runs underground from the back of the house to the summer house, terminate the swa in a junction box inside the summer house, run twin and earth out to the sockets in series.

My main questions are:

-What size cabling should I use? (I figured 4mm SWA and 2.5mm T&E but wasn't sure about factors such as volt drop)

-Do I need any additional circuit protection inside the summer house?

-Is it acceptable to use the 3rd core of the SWA as a cpc rather than the armour?

-Seeing as taking the supply directly from the consmer unit has been ruled out, are there any better/safer/easier options to spurring?

Any advice you can offer would be greatly appreciated - thanks

 

[Octopus]

Because I would pay you. I thought most electricians sign off other peoples work from time to time?

When I say "sign off" I mean tell you that you are planning to do it right and most DIYer's say they will say they will get it signed off but have absolutely no intention of doing so.

Is it your garden or your uncles - you are inconsistent.

 

[micknew]

Another DIYer trying to pick our brains to save money.

 

[micknew]

This forum is for discussing unusual problems not for giving step by step instructions to B&Q customers.

 

[AD23]

Right, before I get any more sniping I think I need to clear a few things up. I am not another B&Q customer, and quite frankly to just assume so is disrespectful. You don't know the first thing about me, and I never felt the need to give you a back story but maybe now I should. Far from being a DIYer I actually passed my C&G 2330 with distinction in all units last year. I have been actively looking for work within the industry, looking to also add my 2391 and 2356 but several unfortunate personal and financial setbacks have made that extremely difficult for the time being. As I'm sure all you qualified sparks will agree doing it in the classroom is one thing, doing it out there in the real world is quite another - and as someone who lacks some of the practical experience required I came to this forum seeking support and advice.
Micknew, I thought that the fact I've been given a job spec that forbids the removal of flooring or addition of trunking in order to make this a dedicated circuit at the CU might well qualify this as being an unusual problem.
Murdoch, you asked ME why you should sign off MY design hence why I said I would pay you. If you are unable to grasp basic english, maybe you should be posting on the Plumbers Forum :wink_smile:
I have a beligerant uncle who wants this job done as quickly and cheaply as possible, as I'm sure most of your clients would. I know the importance of putting safety first, but he is determined to go ahead regardless and I want to be there to make sure it's done right.
I know I lack experience and have a long way to go, but I know with the right guidance I can do it right. I'll even pay to notify Building control and get it signed off by a qualified spark myself if needs be!
If my proposal is shot, then I can accept that, all I want is to know if I'm on the right tracks, or if I should go back to the drawing board.
Thanks guys, I genuinely do appreciate your input.

 

[micknew]

Seems to be a few posts at the moment asking how to do extension/summerhouse work.
Spring DIY time?

 

[AD23]

Probably Mick, but not in my case. Are you able/willing to help me?

 

[GLENNSPARK]

why would someone who has saved up and gone through the necessary steps...or jumped through the series of hoops put in front of you...whatever you want to call it.....why should they ..
1) sign off someone elses design....i know i wouldn`t
2)start giving out loads of free advice...therfore encouraging DIY install where the DIYer probably wont possess the necessary tools and experience to carry out all the relevent tasks/procedures correctly (safe isolation?) for a start...
3)contravene the part p scheme rules and therefore risk the comeback for this...
4)risk someones dodgy uncle who will hold the name on the cert accountable to any shoddy work done..(regardless of who actually installed it)....

i mean come on....your having a laugh arn`t you....

 

[Marvo]

-What size cabling should I use? (I figured 4mm SWA and 2.5mm T&E but wasn't sure about factors such as volt drop)

2.5 SWA would be fine, you can use 4mm if you think he'll need future provision for more power.

-Do I need any additional circuit protection inside the summer house?

Not sure about UK regs but I would consider mounting the RCD in the outbuilding and spurring off with a standard FCU type arrangement at the house. This would be more user friendly not having to walk to reset as well as being a method of local isolation etc. Like I say check your local regs first.

-Is it acceptable to use the 3rd core of the SWA as a cpc rather than the armour?

Use the third core as well as the armour. Terminate the SWA with appropriate glands and use earth rings (banjos) at both ends to bond the armour. I imagine the UK regs will require this.

-Seeing as taking the supply directly from the consmer unit has been ruled out, are there any better/safer/easier options to spurring?

Impossible To say without seeing the job.

I have no idea what your qualifications allow you to do but if you're not competent to do this work please don't.