WIRING A SHED

[ZZIP2004]

Hi

I have had a new shed installed in the back garden about 3 meters away from the house. I want to install 2 double socket, light switch and florescent light fitting. I am planning to take a feed for the electrics from a socket in my back bedroom then run the cable (all in trunking) to an 13 amp fcu then run the cable up the wall to ceiling height and then through the wall to the outside and then hook the cable on to the wall with a wall anchor before it goes overhead into the top of the shed to feed 2 double sockets and the light switch for the light. Is a fixed 13 amp fcu the correct way or would it be better with a 13 amp rcd 30ma spur? Also what is the best way of attaching the cable to the outside wall, what are the wall anchors called for cable? I would only be using the power in the shed for a lawnmower, 12volt garden lights and the occasional power tool.

Thanks

Stuart

 

[PrenticeBoyofDerry]

I have had a new shed installed in the back garden about 3 meters away from the house.

Nice

I want to install 2 double socket, light switch and florescent light fitting.

Is this within the scope of your ability to do this, as required by part p (building regs) and as outlined in BS7671:2008?

I am planning to take a feed for the electrics from a socket in my back bedroom then run the cable (all in trunking) to an 13 amp fcu then run the cable up the wall to ceiling height and then through the wall to the outside and then hook the cable on to the wall with a wall anchor before it goes overhead into the top of the shed

What type of cable, what overhead height and distance? What goes on in the area that the cable will be overhead height? any vehicular traffic and how will the cable be supported over this distance.
Is the socket you intend to spur from, suitable to able to do this?

Is a fixed 13 amp fcu the correct way or would it be better with a 13 amp rcd 30ma spur?

It would depend, is there already 30mA protection on the circuit you are spurring from, if so no real need to add to it. If none, then there are number of ways to satisfy the requirements, which state that any new cable buried within walls at a depth less than 50mm, that is not mechanically protected or specialised earth shielded cable used will require RCD protection, it also goes on to state that new socket outlets will also require RCD protection

so what is the best way of attaching the cable to the outside wall, what are the wall anchors called for cable?

Catenary

I would only be using the power in the shed for a lawnmower, 12volt garden lights and the occasional power tool.

What occasional power tools?
With a 13A FCU, you will only be allowed a 13A maximum load within the shed.

 

[ericmark]

I will shorten to two points.
1) RCD will depend on what is already installed.
2) Out side cable needs to be designed for out side and that does not include twin and earth.

Likely you will need some junction boxes where you swap cable type.

 

[ZZIP2004]

The cable will be coming through the wall in the back room about 8 feet high from the ground slabbed area in the back garden, the distance is less than 3 meters, the cable I intend to use is 2.5mm T&E. I plan to support the cable onto the house wall with a wall anchor then onto the shed with another anchor. The socket I intend to spur from is part of the ring main protected with a 30 amp mcb. I plan to run the cable in trunking in the inside of the back bedroom from the socket to a fused spur then up the wall in trunking then outside so I would not be burying the cable in the wall.

Any power tools would be a drill, jigsaw, circular saw etc nothing heavy like a heater

 

[PrenticeBoyofDerry]

Cannot use T&E, externally need a cable more suitable for the external environment.
Cable will require to be supported at a height no less than 3.5m (if I remember correctly) for areas where access by vehicles is non-existent.
RFC socket one spur only per socket, cannot spur from a spur, so you need to confirm that the socket is suitable.
Power tools, garden tools plus light, limited to 13A full load.
30A circuit would suggest unlikely to have 30mA RCD protection, you can get 30mA combined RCD/FCUs.

 

[Robin0577]

Even shortened, I think the OP may have missed one of your points Ericmark, so I'll just make it a bit bigger for you....

2) Out side cable needs to be designed for out side and that does not include twin and earth.

 

[ZZIP2004]

So I would be better with a 30mA combined RCD/FCU ? Also I can make the cable go up the wall further so it is at least 3.5m above ground level. You say that T & E isn't suitable for outside work, I have noticed many installations with T & E used outside over the years, infact my dad built a new garage 20 years ago and the cable comes from the eves of the house fed from the CU down to his garage CU and has never had a problem and that garage has been well used over the years with plenty of power tools

 

[Risteard]

I think what they are trying to say is that T&E is a rubbish enough cable type when used indoors, and is even more rubbish used outdoors. It is also not designed to prevent UV degradation, although in reality this is not likely to be a huge issue.

Use something more appropriate.

 

[PrenticeBoyofDerry]

So I would be better with a 30mA combined RCD/FCU ?

I would say with the work you intend to do yes it would be, but you need to confirm that it does not exist already on the circuit, having two RCD devices on a circuit is not a complete no no, but is not required.

Also I can make the cable go up the wall further so it is at least 3.5m above ground level.

That would then comply to the requirements

You say that T & E isn't suitable for outside work, I have noticed many installations with T & E used outside over the years

Because the people that installed them are ignorant to the capabilities of this materail

infact my dad built a new garage 20 years ago and the cable comes from the eves of the house fed from the CU down to his garage CU

Your dad not a competent electrician then?

and has never had a problem and that garage has been well used over the years with plenty of power tools

When was the last time the circuit was inspected and tested and the condition of the sheath and insulation investigated.

T&E is not designed to deal with the external environment and the external influence that may be put upon it.
Does not like direct sunlight nor does it enjoy extreme frosts. Select another cable type that can deal with the environment.

 

[ZZIP2004]

I can make the cable go up the wall further, that is not a problem.

So basically i have an rcd fixed fused spur in the house then lead out the correct cable into the shed.

Then wire the incoming cable into another 13 amp fcu for sockets (or do i need another fcu for the sockets considering i have an rcd fcu in the house that feeds the shed) and take a spur from this for a 5 amp fcu that will be used for the light?

Or do i make a junction box for the incoming cable in the shed to feed the sockets without an fcu in the shed for the sockets and also have a 5 amp fcu for the lights wired into the junction box


Cheers for the help