Electricity in shed

[Dawid86]

Hey all!
I am building a concrete block shed and summer kitchen at the back of my garden. I am going to run water, internet and power there.
Do i need a qualified electrician to sign it off?
I have some experience with running installations so i can do it safely etc.
Also i am not 100% familiar with the regs. I intend to run all below the frost level, at around 60cm depth. If i run cable in a conduit (can i use standard one or do i need a double walled one?) does it still have to be an armoured cable? These are of course lot more expensive. Also running cat6 eth cable, would it be okay to run it in the same conduit or would you suggest to run a separate one?

 

[Taylortwocities]

Same reply as you had on the Screwfix forum.

You need a registered electrician to design the supply, install test and notify the whole enchilada.

Of course it must be armoured cable. how do you know that 6mm is big enough?

not good plan to have mains and Ethernet in the same duct. There will be electromagnetic interference issues.

 

[Dawid86]

I am going to get an electrician, but want to run a cable beforehand, one piece so someone qualified can fix the screws. Right after my college back home i had electrical qualifications for home installations but that was years back and different country so i am not familiar with the regs, hence question. I am capable though of calculating the size of the cable needed to get enough power for my devices. Also came here instead as for both questions I asked on Screwfix forum i got pointed out how much do i not know (as if i would ask if i knew it all) and to get qualified people to do all my electricity and water supplies. That indeed defies the idea of DIY. I know ot will take me a while to build the shed and put roof on it so wanted to already run cables and pipes through footings to be connected later to house cu and new cu in the shed. Pipes i 100% know i can do myself so this is easy, and already got soke great advises in here. Also does it mean i need both, the armoured cable and ducting? And would it be a regular ducting?

 

[Taylortwocities]

Your problem is that Installations like this need certifying snd notifying to the local authority. Registered electricians can only notify work they have done themselves. Also the installation certificate states that the person signing (your mug electrician) has designed, installed and tested it himself.
Anyone worth his salt Won’t be happy with being presented with the ends of some cables designed by asking some random questions on the Internet, installed and buried By you so it cannot be inspected.

Some may let you do some grunt work but You need to involve your mug Electrician from the start. They can then advise and guide your process.

 

[flameport]

Also does it mean i need both, the armoured cable and ducting? And would it be a regular ducting?

Armoured cable can be buried directly in the ground.
Or it can be installed in ducting, the benefit of that being that the ducting can be installed first, and the appropriate cable(s) pulled in later.
Twinwall ducting is preferred as the inside is smooth and it is usually supplied with a draw wire already inside.

Do i need a qualified electrician to sign it off?

I am going to get an electrician

Whether you get an electrician involved is up to you, but if you do, you must be sure of exactly what you want from them first.

If you want the electrical work notifying to building control there are two choices - either you do the notification yourself, or the electrician does the work and the notification.
There isn't any other realistic option, and you doing the work and expecting someone else to notify it afterwards won't happen.

If you want the electrical work to be inspected and tested, and some type of certificate provided with the results of that, then you will need to get an electrician involved before anything is installed.
You installing some or part of it and then expecting someone to do the rest and provide a certificate is likely to end badly.

 

[Dawid86]

I did not refer to a qualified electrician as mug at any point. You seem to be easily offended and believe pulling a cable through the conduit and footing to the shed requires some level of sacred knowledge. I do not mean to offend anyone who went to school to get their qualifications though, i simply had that in my college and then uni too. I mearly said i could dig a trench and pull cable from one end to another and i have no clue how could that be done wrong, unless i would somehow damage the cable in a process or decide to wrap it in a coil for some completely unknown reason. And since i am about to start with laying foundations i wanted to at least pull the conduit through the footing so that i have it in and out of shed ready for doing stuff with it later. Hence a question about the conduit and type of cable. I am also struggling to understand why the type of conduit would have to provoded by a person designing it as this is going to be either standard or reinforced one, surely based on regs. I will get in touch with the builders who did some work at my workplace to get me in touch with their electrician, hopefully he will be happy to tell me what materials to use and then take it from there with me.

 

[Dawid86]

Ok thanks both, will get in touch with them now and see where it takes me. If they won't be available yet i will pull the twin walles conduit through to the shed so that i can carry on the works without waiting for them.

 

[oldbutnotdead]

What they said above. You need to get hold of your electrician now, tell them what you want (in terms of how much power in the garage), let them design the scheme (6mm 3 core SWA will probably be ok up to 30 metres unless you're planning on running a big TIG) and take it from there.
Yes you digging the trench to your electricians spec is a sensible idea.
No don't put CAT6 and SWA in the same duct. SWA can be buried direct but (if you can't get a spark on the job right now) just bury 2 40mm twinwall ducts to the standard spec (750mm, 100mm sand round the ducts, warning tapes, solid cover, backfill and minimum bend radius for up to 16mm SWA). Take pics.

If you're running water to the shed you'll need drainage there as well (you can't chuck grey water into a soakaway). Think about having a loo there as well. And maybe even a shower (that'll affect your cable size also).

 

[Dawid86]

Thanks!
Regarding the drainage, the shed is much lower than the house so would need a grey water pump. Those thend to be a big disappointment, or at least so i heard, and septic tank would be an overkill for one sink next to bbq, so i was advised to use the rollalong water container you use for campers. Easy and simple!
Defo not going to chuck grey water direct to soakaway. I was considering some sand filter or small septic tank and then overflow to soakaway, but, as i said, that seems like a bit much for what it needs to do.

 

[oldbutnotdead]

I got pulled up on this, Saniflos and similar used to be noisy unreliable pains but apparently they've improved.

I could see slopping out the sink waste getting very boring very quickly....

 

[Dawid86]

Yeah, but 45 liters container and if i only use it to wash my hands after touching meat etc so that i don't spread stuff from meat onto other food and don't run with greasy hands,should last for a few days. Not planning any shower etc, as i can walk 20m home for that, it's just i have that obsession of washing hands often while cooking

 

[oldbutnotdead]

Fair enough but i think you'll regret not doing it in the long run plus Building Control (if they're involved) may get a bit sniffy. You're already committed to digging a trench, I'd stick the relevant pipework in while the hole is there. Though saying that i don't know if Saniflo etc will deal with a long uphill run...
EDIT Just checked, some do. Google is your friend...

 

[Dawid86]

Yeah I am a bit resilient about the pipes going 25 meters from back of the shed up to the sewer and then if the pump wont do the job it will just all go to waste. Or if the water will be under a little pressue and it develops a blockage somewhere halfway through the garden in that tiny pipe, that would also be nice. I think the tank will be fine with the building control (assuming they ever see it) since i will be collecting all the grey water and disposing off to the existing drainage. My project is already quite big and complex and don't want to add complexity where it is not needed. Basically where it is now - 7x5m shed, insulated, 7x5 outdoor kitchen sharing a wall and roof with shed, with gas bbq, hob, sink, little fridge, log burner for chilly evenings. Both covered with a green roof, gutter to the barrel and overflow to soakaway. Shed connected to a cage for chicken (yeah, my partner wants chicken) with automated door to let them out not too early - don't want to wake up with sun if i don't have to. Then internet, and some smart tech in there (programming own smarthome system based on openhab so can connect stuff in there accordingly). I therefore keep adding stuff and risking never completing it

 

[oldbutnotdead]

At 35 sq m thats a notifiable structure. Presumably you've got a massive garden so no problems with 50% or 2m of boundary?
Hob-electric? That'll affect your electricity supply requirement

 

[Dawid86]

Yeah i have a big garden so it is way below the 50% of area. Gas hob, two burners running off gas bottle just as the bbq. Roof at highest point 2.5m. Already contacted local planning institution and they said i will not need a planning permission for that