Routing power cables outside to shed

[GrumpyShedMonster]

Now its getting dark in the evenings, I want to route power to my shed.

I could take a spur off a wall socket in the kitchen - as this is the nearest point to the shed.

But what is the best way to get the power cable through an outside wall? and what kind of cable or conduit would you use.

And its a bit of a convoluted route to the shed - over paving slabs and along walls & fences. If the cable does go on the ground it would cross a patio, then over a small wall, along a woodern fence, then down to the shed. It would be much simpler to have an overhead cable - but there's bound to be some safety regulation preventing this.

 

[PrenticeBoyofDerry]

the cable you need is swa(steel wired armoured).
It should be routed underground or clipped to a secure surface and not run along the ground.
It would ideal for this circuit to be on it's own MCB or RCBO it must have RCD protection and is considered notifiable work, so application to building controls are needed. Part P of building regulations to be complied to.
The cable can be installed at heights where no through traffic of vehicles are.
This too may need support by a catenary wire. The height off top of my head is 3.5m but will stand to be corrected.

 

[chapeau]

Overhead cables are allowed but it's usually considered better/safer to run the cable underground. You are correct in that there are many regulations which can give guidance on how to do this safely, and the law also rears its ugly head when dealing with this. A search will throw up no end of threads on the subject.

 

[ban-all-sheds]

Now its getting dark in the evenings, I want to route power to my shed.

How far away is it?

What loads will you be powering in the shed?

Both of those factors affect the size of cable you need: http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html

I could take a spur off a wall socket in the kitchen - as this is the nearest point to the shed.

That may not be the best source. Is that circuit RCD protected?

Will a spur provide sufficient power in the shed?

But what is the best way to get the power cable through an outside wall?

By drilling a hole in it. Angled downwards as it goes out, to stop water getting in. Is it a cavity or solid wall? If the former is there insulation in the cavity?

and what kind of cable or conduit would you use.

Conduit is usually a pain - best to use armoured cable.

And its a bit of a convoluted route to the shed - over paving slabs and along walls & fences. If the cable does go on the ground it would cross a patio, then over a small wall, along a woodern fence, then down to the shed.

It can't go over that, it would have to go underground. Or overhead.

It would be much simpler to have an overhead cable - but there's bound to be some safety regulation preventing this.

There isn't, provided it's done safely.

The cable has to be an appropriate type, it has to be supported (e.g. on a catenary wire, not taking its own weight), and the minimum height above the ground should be 3.5m, or 5.2m if vehicles will pass underneath.

The regulations which you should be aware of include the Building Regulations: //www.diynot.com/wiki/electrics:part-p

 

[GrumpyShedMonster]

Thanks for all the information.

In reply to points raised.

The Shed is only about 5metres away in a straight line, but to route a cable, keeping to the edges of the patio, and along the fence the cable length would be about 11 metres. I have been using an extension cable, but its a trip hazard, needs an open door or window and I'm not sure if its safe in the rain.

The loads would be for a couple of lights, radio, drill, jig-saw - (no heaters, or TV - its a workshop not a lounge!)

Not sure what RCD protection is, but the house fuse box has six fuse slots, and all of them are in use. The kitchen/downstairs ring main has a 30A fuse, so I'd assume a spur of the kitchen main would provide easily enough power.

Its a cavity wall without insulation. but there is a nearby existing hole (used to be the waste outlet for a dishwasher which has been resited) - anything wrong with using that?

It looks like overhead is out because the shed level is about 2meters lower than the house, so the cable, angled down would at some point be lower than 2.5 meters off the ground,.

Is there a 'Definitions' page to find out what the terms mean
specifically MCB, RCBO, RCD?

 

[chapeau]

Not sure what RCD protection is,

The first thing you should do is go and purchase one of these http://www.screwfix.com/prods/15263/Electrical-Supplies/RCDs/RCD-Adaptor adaptors, plug that into the socket, and then plug your shed extension cable into the RCD. This will give a huge amount of protection if you accidently damage the extension cable and risk a shock.

Then you can decide how to put in power over the longer term.

 

[PrenticeBoyofDerry]

Your fuse box want have
RCD Residual current Device
MCB Miniture Circuit Breakers
RCBO Residual Current Breaker with Overload protection.
To be honest I'd get a qualified electrician in.

 

[GrumpyShedMonster]

Your fuse box want have
RCD Residual current Device
MCB Miniture Circuit Breakers
RCBO Residual Current Breaker with Overload protection.
To be honest I'd get a qualified electrician in.

Nothings ever simple these days.

I had an electrician quote me for a new socket for the top of the stairs. When he saw the fuse box he advised a complete rewire of the house, (over 2000 quid) and said if he onldy did the socket he wouln't be able to guarantee the work on it (for 175 quid - its in an awkward place, needed carpets, floorboard lifting, plastering etc). I did the socket myself in the end

So my house is obsolete where qualified electricians are concerned.

 

[bongos]

There is a definitions page on this site.

As stated it will be best getting an electrician in as by the time you have notified the work to the LABC and bought the materials yourself it will probably be around the same anyway.

I had an electrician quote me for a new socket for the top of the stairs. When he saw the fuse box he advised a complete rewire of the house, (over 2000 quid) and said if he onldy did the socket he wouln't be able to guarantee the work on it (for 175 quid - its in an awkward place, needed carpets, floorboard lifting, plastering etc). I did the socket myself in the end

If he said that just by looking at the fuseboard then you need another electrician! Yes, a new socket would require 30mA RCD protection but that does not mean you need the house rewiring.

It might be an idea to look at getting your fusebox updated though as a new one would incorporate RCD's, with that the spark could also install a new circuit to the shed. It's also quite likely that a spark will let you do all the digging and heavy stuff for a supply to your shed and then they will do the rest but if you decide on this option make you speak to one first before starting any work.

Have a look here for more info on diy electrical work.

 

[PrenticeBoyofDerry]

Your fuse box want have
RCD Residual current Device
MCB Miniture Circuit Breakers
RCBO Residual Current Breaker with Overload protection.
To be honest I'd get a qualified electrician in.

Nothings ever simple these days.

I had an electrician quote me for a new socket for the top of the stairs. When he saw the fuse box he advised a complete rewire of the house, (over 2000 quid) and said if he onldy did the socket he wouln't be able to guarantee the work on it (for 175 quid - its in an awkward place, needed carpets, floorboard lifting, plastering etc). I did the socket myself in the end

So my house is obsolete where qualified electricians are concerned.

The problem you have is your installation is quite old and with new requirements, in some areas you may need an upgrade.
When installing new circuits or addition or extending old circuits the regulations point towards protecting the circuits or new work with residual current devices, this would be normally RCD/RCCB/RCBOs.
As regards the re-wire, that would depend what condition your installation is in, but it's quite often suggested that a new consumer unit is installed that has an RCD on it.

 

[ban-all-sheds]

If he said that just by looking at the fuseboard then you need another electrician!

Not if what he could see were VIR cables leaving the CU...

 

[ban-all-sheds]

The Shed is only about 5metres away in a straight line, but to route a cable, keeping to the edges of the patio, and along the fence

Routing it along the fence might not be acceptable

the cable length would be about 11 metres.

Then you need to account for that distance in sizing the cable. In the calculator I linked to select 2-core PVC SWA, and see what it comes up with.

Not sure what RCD protection is,

• http://en.wikipedia.org/wiki/Residual-current_device
• http://www.westernautomation.com/pages/demystify.htm
• http://www.memonline.com/guide06.html[/list]
  
  
  

  The kitchen/downstairs ring main has a 30A fuse, so I'd assume a spur of the kitchen main would provide easily enough power.

  Your spur would be limited to 13A, not 30....
  
  
  

  Its a cavity wall without insulation. but there is a nearby existing hole (used to be the waste outlet for a dishwasher which has been resited) - anything wrong with using that?

  Nope.
  
  
  

  It looks like overhead is out because the shed level is about 2meters lower than the house, so the cable, angled down would at some point be lower than 2.5 meters off the ground,.

  Put a pole on the shed to provide a higher point?
  
  
  

  Is there a 'Definitions' page to find out what the terms mean
  specifically MCB, RCBO, RCD?

  //www.diynot.com/forums/viewtopic.php?p=111778#111778
  
  But as the others have said, there's a lot more to doing all of this than you imagine, there are legal implications, changes to your existing installation may be needed, and overall I think it's too big a task for you right now - I urge you to get an electrician to do it.

 

[jso]

It looks like overhead is out because the shed level is about 2meters lower than the house, so the cable, angled down would at some point be lower than 2.5 meters off the ground,.

Could you not attach a rigid vertical fitting to the side of the shed, some kind of steel pipe, or eg angle iron, to allow for a horizontal run of overhead cable at the permitted height, then just run the cable down this "mast" and into the shed?
I don't know if that would be acceptable - I just mention it because I have a similar system in reverse - a vertical bracket on the garage wall takes the cable (plugged into a garage socket) to an appropriate height for a short run across to a woodshed (to power a light fitting inside the shed.). The cable is supported on a tensioned wire.

 

[ban-all-sheds]

Put a pole on the shed to provide a higher point?

 

[jso]

Put a pole on the shed to provide a higher point?

sorry ban-all-sheds:
So you did! I mised that particualr line (although I had read your other comments in that posting.