Laying electric to workshop - best way

[Grahamshed]

For the last 12 years ( raises eyebrows and shudders ) my 'shed' has been supplied by an extension cable strung up from the house about 30 feet away.

Now I am using it as a workshop I want to get a proper loop supply in there and I am thinking of how best to do it without laying out a fortune for armoured cable.

I want to do most of the work myself and then just get it checked but am unsure of the acceptable ways. What have you guys done ?

 

[MickCheese]

Armoured cable from a junction box at the consumer unit to a consumer unit in the workshop.

Mick

 

[ash224w]

Armoured cable from a junction box at the consumer unit to a consumer unit in the workshop.

Mick

plus 1 on that you do need a good supply and when you get the final number of socket you require double it and one thing i all ways do i have a 110V transformer permanently wired in to its own supply and fuse spur

 

[wobblycogs]

I echo what others have said. Whatever you do don't skimp on the cable you lay to the shed because you'll require more power than you think you will and it'll be a pain to change later. Armoured cable buried in the garden is the way forward, you should easily be able to do most of the work yourself e.g digging the trench and sticking the cable in it. Depending on how hard it is to get from the outside wall to your main fuse box you might want to let the sparky do that section as it can be hard work to run in heavy cables.

 

[Wildman]

so hooking into the street light is a no no then?????

 

[Grahamshed]

so hooking into the street light is a no no then?????

Answer 1.... Now he tells me !!!

Answer 2.... You have street lighting where you live ? There's posh then.

Answer 3.... Not related to this but do you have a motorhome Wildman ?

 

[Grahamshed]

Any idea how deep armoured cable has to be ? and how much it costs ?

 

[wobblycogs]

There's a write up at TLC: http://www.tlc-direct.co.uk/Book/7.13.3.htm. Basically you have to put the cable deep enough that it will reasonably avoid normal activity. Running across a garden I'd say 500mm unless it's passing though somewhere you're double digging.

When we had the main incoming cable for the house replaced I dug down 600mm in the front garden. When they came to replace the cable they didn't bring enough (cretins) so they ran it at only 300mm deep. It passed inspection fine though. I asked the inspector why it passed as I could hit it with a spade while digging. His response was something like "you could hit it with a spade all day and not make a dent".

Also, while the regs say you should have it buried in sand with warning tape over it etc etc I think you'd be hard pressed to find anyone that would actually make you do that. Just ensure you are throwing dirty great stones in with the cable that will press into it and damage the outer sheath.

You'll be wanting to sink a minimum of 6mm cable but personally I'd say 10mm is the minimum worth putting in - depending on the length of the run you might need to go even higher. A 25m reel of 10mm will cost you about £125: http://www.screwfix.com/p/prysmian-lv-armoured-3-core-black-10mm-25m-cable-reel/21963.

 

[Grahamshed]

Thanks Wobblycogs, thats more than helpful. Cheaper then I was expecting and it never occured to me it would be as easy to find as screwfix.

Thanks to everyone else as well.

 

[Grahamshed]

If the cable is going to go from the house consumer unit to another one in the workshop......... is that a one way trip or a return ?

 

[wobblycogs]

You only need a single run of cable from your main fuse box in the house to a fuse box in the shed. Your sparky will probably specify a three core cable. I believe you can get twin core but I didn't see any at ScrewFix when I had a quick look. Three core is probably better as you can use the spare conductor as an additional earth.

 

[Grahamshed]

Many thanks.

 

[MickCheese]

If the run is not too long you could suspend it above head height.

I used meter tails to a junction box then to the armoured cable then I ended at another junction box and metre tails to the workshop consumer unit.

Mick

 

[Grahamshed]

If the run is not too long you could suspend it above head height.

I used meter tails to a junction box then to the armoured cable then I ended at another junction box and metre tails to the workshop consumer unit.

Mick

Hi Mick. Were those junction boxes indoors or out ?

 

[flying haggis]

As the above have said, SWA fed from your main consumer unit then buried to the shed and connected to a small consumer unit in the shed. As you are in Oxford this work is notifiable so a sparky will have to sign it off and he/she will have to do the calcs for cable size etc

and for interest 25m of 6mm SWA delivered to your door £83.50 from here

http://www.ebay.co.uk/itm/6mm-3-core-St ... 231570fccf

 

[MickCheese]

If the run is not too long you could suspend it above head height.

I used meter tails to a junction box then to the armoured cable then I ended at another junction box and metre tails to the workshop consumer unit.

Mick

Hi Mick. Were those junction boxes indoors or out ?

They were both indoors. Just normal black metal boxes with knockouts and the special armoured cable fittings into heavy duty strip connectors.

Mick

 

[misterfish]

I've seen SWA neatly fixed to walls and fences above ground level where the shed was close to the fence. The other thing is overhead wiring using a catenary wire to support the cable - I helped my brother-in-law set up an overhead cable to a new barn on his farm.

For my workshop the builders first installed a 2 inch diameter underground trunking pipe that the sparks later pulled SWA through.

Misterfish

 

[RogerS]

.....
For my workshop the builders first installed a 2 inch diameter underground trunking pipe that the sparks later pulled SWA through.

Misterfish

That's what I did and also ran plastic water pipe, an ethernet cable, and a pull-through for future use.

 

[Elapid]

Cable is £1.21 a metre here:- http://www.ebay.co.uk/itm/SWA-armoured- ... 780wt_1037

 

[Phil Pascoe]

Once more my last post disappeared into the ether - try again.
I pulled a two way light switch wire through mine