Power to the shed

[Rick Sanchez]

I'm about to turf my lawn and thought it would be a good opportunity to run some power to my shed. My plan was to run some swa 50 cm deep, and connect it off of a spur inside my house. At the other end I would just run a socket and light.

I've read some conflicting information online, so my question is, is there a way for me to do this and be compliant. I don't want to invalidate my insurance etc. If its not something I can just do myself for next to nothing I won't bother.

My current wiring does not have RCD.

 

[oldbutnotdead]

Yes there is an easy way to do this so it complies- get an electrician in. The job will cost a fair few quid (depends how far your shed is from the house but allow £150-£200 for a days work from the electrician). SWA- without knowing the length of the run it is impossible to determine what size cable is required. If you've got a path up the garden (of concrete slabs) then 'adequate protection' could consist of laying the cable under the slabs. Otherwise bury it deep (600mm plus) with marker tape and solids to prevent accidental penetration of the cable. But that's all up to your electrician- they are the one taking responsibility for the installation so it is their call as to how deep.

 

[Taylortwocities]

My plan was to run some swa

That's the first thing to be determined. "SOME SWA" isn't good enough.
Need to know the projected total load - whats out there, lathe, engine hoist, MIG welder, 10KW instant shower?
And then the distance from the intake.
And then the supply type
and then the...... lots more questions.

My suggestion is that you just run in a length of service duct. Like this
http://www.drainageonline.co.uk/Ducting/Black-Twinwall-Duct-x-50m-coil.htm
Also, you need to get a registered electrician to do the cable calculations, pull the cable into the duct, connect up, certify and (importantly) NOTIFY the whole thing to the local authority.

 

[JohnW2]

Also, you need to get a registered electrician to ..... and (importantly) NOTIFY the whole thing to the local authority.

Whilst I agree with the rest of what you say, if this work were done as the OP suggested (extending an existing circuit to supply lighting and one socket in the shed) then, if the OP is in England, the work would probably not be notifiable.

Kind Regards. John

 

[Taylortwocities]

(extending an existing circuit to supply lighting and one socket in the shed)

Whoops, missed that

 

[charliegolf]

I had that done recently, 54 metres of SWA, double external socket and it cost me £350. The electrician was happy for me to dig and lay the cable.

 

[ban-all-sheds]

Why go to all the effort of digging a trench and burying a cable that would only ever be of use to supply one socket and a light?

 

[PTS2]

My plan was to run some swa 50 cm deep, and connect it off of a spur inside my house. At the other end I would just run a socket and light

Spur to a weatherproof RCD socket on outside house wall and buy an extension cable to plug into it.

 

[ban-all-sheds]

And then the extension cable will be left plugged in all the time.

Your suggestion is a dreadful one - a shed is not an appliance, and should not be supplied via a plug and socket. Plus how would you ensure that the flex was safely routed?

A dreadful bodge.

 

[charliegolf]

Why go to all the effort of digging a trench and burying a cable that would only ever be of use to supply one socket and a light?

Dunno if that was for me... but my shed is my 'workshop'. I have most common power tools in there, and can only use one at a time, so only need one socket. £350 was a bargain to avoid a 45m extension cable every time I wanted to use a drill.

 

[ban-all-sheds]

Dunno if that was for me...

No, it was for the OP.

Particularly when employing an electrician, the total cost of the job is not increased by much of a % by using a larger cable than is strictly necessary for just 1 socket and a light. It is worth at least considering the "insurance" aspect of that materials premium against the cost and aggro of having to do it all over again if the requirements go up.

 

[Rick Sanchez]

Thanks for the advice everyone.

Ok so here is the cable I am planning to use.

https://www.screwfix.com/p/prysmian-lv-armoured-6943x-3-core-cable-2-5mm-x-10m-black/33784

Why go to all the effort of digging a trench and burying a cable that would only ever be of use to supply one socket and a light?

Its really no effort as I have dug up the entire lawn already, just a case of spending £20 so I can run some power so I can have a light and a socket in there. My sheds not a workshop so I will only ever use a little power up there, nothing permanent.

In my family there is a highly skilled commercial electrician who will do the work for free, they just aren't Part P as they don't do domestic. If its not notifiable then this should be sufficient. It will just run off of an existing circuit as mentioned before.

Whilst I agree with the rest of what you say, if this work were done as the OP suggested (extending an existing circuit to supply lighting and one socket in the shed) then, if the OP is in England, the work would probably not be notifiable.

Do you think its not notifiable based on what I have described?

Many thanks

 

[JohnW2]

Do you think its not notifiable based on what I have described?

If you extend an existing circuit to just supply a light and a socket in the shed, then that work would not be notifiable in England.

If you did that, I would suggest that you should not make the 'mistake' of (unnecessarily) putting a 'mini consumer unit' (e.g. a 'garage' CU) in the shed - since, silly though it may be (in my opinion!), some would then argue that the work had suddenly become notifiable. If you take the supply directly to the socket, and via an FCU (with 3A fuse) from socket to the light, then it would definitely not be notifiable. If you used a switched FCU, that could serve as the light switch.

However, I am inclined to agree with BAS. Even though you do not currently envisage ever having any greater needs, if I were going to the trouble of digging a trench and buying/installing SWA, I think I would put in a hefty enough cable to serve greater loads in the future, should the need ever arise. However, that's obviously up to you!

Kind Regards, John

 

[EFLImpudence]

If you extend an existing circuit to just supply a light and a socket in the shed, then that work would not be notifiable in England.

Agreed.

If you did that, I would suggest that you should not make the 'mistake' of (unnecessarily) putting a 'mini consumer unit' (e.g. a 'garage' CU) in the shed - since, silly though it may be (in my opinion!), some would then argue that the work had suddenly become notifiable.

I would say not as he is not "replacing" a consumer unit.
It could justifiably be called stupid but that is what they wrote.

 

[JohnW2]

Agreed.

Thanks. You need to add a quote tag to your post.

I would say not as he is not "replacing" a consumer unit. It could justifiably be called stupid but that is what they wrote.

Agreed. However, as you know, some people say that, regardless of what they wrote, it is 'obvious' that it is meant to include the installation of a new/additional CU (i.e. not 'replacing' a previous one).

In any event, even if one convinces people that they have to go by 'what has actually been written', some will then switch to arguing that the socket and light originating from the new CU are 'new circuits' - hence, again, notifiable.

I can't really be doing with those silly arguments/discussions so, as I did with the OP, I now tend to advise people to avoid these (unnecessary) mini-CUs, and hence also avoid the arguments!

Kind Regards, John