Power For Shed and Greenhouse

Evening. Could someone help me with a project that I’m working on. Apologies if this has already been discussed.

I’m erecting a joint shed and greenhouse at the bottom of our garden and would like to run some power to it. The power will be for lights and power sockets both in the greenhouse and shed. There will not be any heavy loads that a normal 13amp plug cannot support. The shed/greenhouse is about 13m from the house. The power will be connected to the house consumer unit that is presently in our garage.

I’m planning on getting a qualified spark to connect the power up to the consumer unit and sign it off for building control. But wanted to do some of the digging and cable runs myself to save money.

My initial idea is to run a length of flexible conduit underground at a depth of about 500mm from the garage to the shed and then a length of 10mm twin and earth through the conduit. I appreciate that twin and earth isn’t deigned for this purpose but given that it will be contained within a conduit then I figured that it would be ok. This cable would be connected to a consumer unit in the shed which would slit the light and socket circuits.

My question is:

1.       Would the twin and earth be ok or should I use 10mm SWA cable

2.       Do you think that a 10mm cable would be ok or would you recommend something else

3.       What size flexible conduit would you recommend to allow the cable to be easily dragged through

Thanks for any help

Ask the qualified spark for his advice. He’s the one who will be doing the job and you wouldn’t want to annoy him by installing the wrong cable

+1

And, I wouldn't even entertain it in T&E

SWA is your friend here, 

+2, pipe + T&E = way too much hassle, swa cheap and easy

Christmas_Jones said:

I’m planning on getting a qualified spark to connect the power up to the consumer unit and sign it off for building control. .

Click to expand...

Phrases such as this general show a limited understanding of an Electrical Installation Certificate (EIC), or 'building control' and especially what the signed declaration of and EIC actually states. So to try and cast a bit more light on what you should have; Firstly irrespective of any 'building control' or what is know as 'Part-P notification', All electrical alterations should be designed, installed and tested in accordance with BS7671 wiring regulations and the appropriate certificate issued. If you are using a three part certificate there will be three separate boxes for Design, Installation and Testing. Whereas a single declaration form has one combined signature for everything. If you are expecting someone else to sign for the design part then, really that is the person you need to ask about what cable and installation methods they would specify. However if you are signing for design yourself, and you only want a third party to sign for testing then indeed select you cables based on whatever research methods you choose, (e.g. books, library, internet). 

Notification for Part-P compliance is normally done by someone who has signed for all three aspects. unless you have contacted your LABC to arrange for them (or their nominated sub-contractor) to undertake the testing. but they will probably want to see your circuit design and any relevant calculations, as if something did go pear shaped then the signed declaration does leave some liability with whoever's name is in the box. For this reason a lot of electricians don't like leaving themselves open to come backs on work they have had no input to the design and specifications of. Best thing to do is find a local electrician who is willing to do the work you want, get them to visit site and advise what size cable they want for the protective devices that are going to be used.

Doc H.  

+3, I'd have you dig it up and install the correct cable.

First job, find the electrician you will be doing the labouring for.

Second job, ask them what they want you to do.

Anything else is a waste of time.

Lurch said:

Anything else is a waste of our time.

Click to expand...

Corrected that for you.

Just get a solar panel and an old car battery, 240v is old hat, all my tools are 18v these days.

Oh and 10mm t&e in flexi conduit! :slap

T&E in flexi conduit underground, No! It will provide very little in the way of protection from damage by say a spade for example, you'll really struggle getting it down a 25mm conduit and the bigger stuff is going to be massively expensive.

I haven't done the calcs, but off the top of my head for such a small load as you are talking then 10mm is way too big even over that distance.

As others have said a length of SWA is the right way to do it, and let your spark decide on the size, if there's a reason why you want to get a cable in first, for example laying a base or sorting the garden then install a 50 mm duct with a draw rope, then the spark can just pull the cable in using the rope.

Don't try and be clever, by doing parts of it yourself then expecting a spark to finish it off, unless you have spoken to the spark first, there's nothing worse than arriving at a job to find someone trying to be helpful has actually made your job harder, plus, lets say you only want a small load around say 16A max, as I said 10mm is way too big and the cable cost for 10mm will be at least double the price for the cable you actually need.

You asked for advice and the guy's here have given you some excellent advice, please take it. 

I don't think we'll be seeing christmas_jones again..................

....................Thank god.

Why do they think we'll fall for the "my electrician" spoof every time.

I think he will be back, I reckon he is down at Homebase taking the 10mm T&E back

Tony S said:

I don't think we'll be seeing christmas_jones again..................

....................Thank god.

Why do they think we'll fall for the "my electrician" spoof every time.

Click to expand...

just saying,

Look at it from his POV, he has read some stuff on the internet, he thinks he knows what he is doing but not sure so he comes to a forum for advice and all he gets is "abuse"

I am not saying what was said is not correct, its just the way it was said.

I get to sit on the fence and watch both sides.

Same as others I wouldnt use T/E but if you insist on wanting to pull 10mm² T/E through duct then you'll want something like this https://www.tlc-direct.co.uk/Products/FXKVR50.html

I'd drop  swa in a trench.............probably  4mm² if only for a socket or two & a light..............but then I have no idea what load you are planning.

Richard-the-ninth said:

just saying,

Look at it from his POV, he has read some stuff on the internet, he thinks he knows what he is doing but not sure so he comes to a forum for advice and all he gets is "abuse"

I am not saying what was said is not correct, its just the way it was said.

I get to sit on the fence and watch both sides.

Click to expand...

Exactly.. What the courgette is the point, when someone comes on here asking for advice, in giving them a whole load of abuse??? How the courgette do you think the forum will survive and prosper what people have attitudes like that???

So as electricians, you might know a lot more about that sort of thing than a beginner, woopy tango'd do, i know a courgette sight more about welding and general engineering than a lot of people on here, but if people ask me for advice i gladly give it, not just launch into a rant about how clever i think i am...

grow up...

john..

Given that the forum advertised it’s self as “The UK’s friendliest electrical forum”. Then I figured that I would receive a respectful response and not the insulting comments of old ignorant retire members that obviously have nothing better to do.

I really appreciate the comments of some members that feel the same about these over the hill old timers.

Lets hope your computer equipment always works lovely and smoothly.

apprentice87 said:

Exactly.. What the courgette is the point, when someone comes on here asking for advice, in giving them a whole load of abuse??? How the courgette do you think the forum will survive and prosper what people have attitudes like that???

So as electricians, you might know a lot more about that sort of thing than a beginner, woopy tango'd do, i know a courgette sight more about welding and general engineering than a lot of people on here, but if people ask me for advice i gladly give it, not just launch into a rant about how clever i think i am...

grow up...

john..

Click to expand...

I’m sorry John if I’ve broken some unwritten rule that I should help a blatantly incompetent DIYer to gain “how to” instructions for notifiable work.

Yes, I have a reputation as being a grumpy old sod but I’m also a good judge of character. In three of my former professions it was essential I could judge someone at the first meeting.

So how would you have responded to the OP?

Christmas_Jones said:

Given that the forum advertised it’s self as “The UK’s friendliest electrical forum”. Then I figured that I would receive a respectful response and not the insulting comments of old ignorant retire members that obviously have nothing better to do.

I really appreciate the comments of some members that feel the same about these over the hill old timers.

Lets hope your computer equipment always works lovely and smoothly.

Click to expand...

Believe it or not the members that have retired from the trade actually have years of experience behind them.

apprentice87 said:

Exactly.. What the courgette is the point, when someone comes on here asking for advice, in giving them a whole load of abuse??? How the courgette do you think the forum will survive and prosper what people have attitudes like that???

So as electricians, you might know a lot more about that sort of thing than a beginner, woopy tango'd do, i know a courgette sight more about welding and general engineering than a lot of people on here, but if people ask me for advice i gladly give it, not just launch into a rant about how clever i think i am...

grow up...

john..

Click to expand...

Why don't you take your courgette's and shove them somewhere your a part of the growing trend to be offended for others without clearly understanding the possible implications

One of the reasons I never offer advice to speculative posts for "how to" advice on electrical is the risk of any comeback would I really want to read in the press that someone had been seriously hurt or killed because that guy on the forum said it was ok or even be stood in court explaining why the I gave advice led to someone getting seriously injured or killed

I will gladly give advice on things where someone's safety and ultimately their life is not, will not and cannot be compromised and I'll let you guess where electrical work stands due to the dangers involved

Christmas_Jones said:

Given that the forum advertised it’s self as “The UK’s friendliest electrical forum”. Then I figured that I would receive a respectful response and not the insulting comments of old ignorant retire members that obviously have nothing better to do.

I really appreciate the comments of some members that feel the same about these over the hill old timers.

Lets hope your computer equipment always works lovely and smoothly.

Click to expand...

If "consult an electrician" offends then pity you and the people in your life close to you

The back of a fag packet design (or a forum) can and often does quite often miss a lot facts pertinent to the design of a safe functional electrical installation if someone looking for advice only gives minimal information on the pretence of getting an electrician in to complete then why not consult the electrician you will use from the start. Statements like that only arouse suspicion, sketches and even drawings often don't give the full picture that a visit to site does

However you feel about the old timers they obviously have a greater respect for electricity than you do and won't compromise your safety by offering advice that may be misinterpreted by you. Electricity is a a lot more than just three wires and lashing in a piece of cable in for a socket and a couple of lights

Not sure what you are getting at with your last line, computers never work lovely and smoothly due to the fact that most of them utilise the windows operating system, the only time I could think of a computer injuring someone would if it was thrown out of an upstairs window and it landed on them when the operating system pushed the user to far

apprentice87 said:

Exactly.. What the courgette is the point, when someone comes on here asking for advice, in giving them a whole load of abuse??? How the courgette do you think the forum will survive and prosper what people have attitudes like that???

So as electricians, you might know a lot more about that sort of thing than a beginner, woopy tango'd do, i know a courgette sight more about welding and general engineering than a lot of people on here, but if people ask me for advice i gladly give it, not just launch into a rant about how clever i think i am...

grow up...

john..

Click to expand...

The problems will arise when people like you dish out advice too all and sundry, irrespective of knowledge, competence and ability and something goes wrong.... Then your advice could land you in court.

Just saying

should we have some kind of shed sticky as this always happens :C