Cable To Shed

[planemad]

I'm going to run a feed out to my shed and garage which are next to each other I plan on having no more than 2 double sockets and a strip light in each.

My consumer is a dual RCD Wylex unit so:

Can I run a cable straight from the CU to the garage/Shed to another small CU?

What size armoured cable should I use? I can surface mount the cable and keep it tidy or I could dig it into the ground.

What do you guys think?

 

[EdwardCurrent]

Hello Planemad,

We need to know the length of run please.

Ed

 

[gcx51]

What is the length of run?

You can run the supply directly from the consumers unit, personally I would fit an rcbo on the unprotected side of the board if available, Reason, if a problem occurs outside it will not effect the electrics within the house.

cleated to the wall is acceptable.

A suitable garage unit is recommended 16A for sockets, 6A for lights.

one more point to make. what earthing arrangement do you have at the cutout? if your unsure what i mean take a picture of where your meter is.

If you have a TNCS or TT you will need to install an earth rod on all supplies run out of the house.

 

[First-time-buyer]

I personally, though as its been pointed out here that you cant carry out electrical work would be too..

Run a 6mm T&E cable from the consumer unit & a 4mm earth (smallest size reasonally available) to a point outside, then here terminate them into a outside plastic box (IP65), from there run a 6mm 3-core armoured cable, use the 3rd cable within the SWA as the earth. This is where the additional 4mm earth comes into play.

On a normal 6mm T&E cable, the earth is 2.5mm, so an overall improvement.

Just dont forget the frying pan ring on the armour.

Gives you the option in the future to increase the amount of points within the garage / shed.

 

[planemad]

Sorry Gents 40ft

 

[planemad]

What is the length of run?

You can run the supply directly from the consumers unit, personally I would fit an rcbo on the unprotected side of the board if available, Reason, if a problem occurs outside it will not effect the electrics within the house.

cleated to the wall is acceptable.

A suitable garage unit is recommended 16A for sockets, 6A for lights.

PS: Board is Dual RCD

 

[EdwardCurrent]

Hello,
Just a thought, are the sockets for a special purpose, do you know what you are going to be 'plugging in' already ?

Regards

Ed

 

[planemad]

They will just be utility sockets, charging drill, operation of power tools but only for short periods of time.
Plug in lawn mower/strimmer.

 

[EdwardCurrent]

Here you go

http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html .

If you do not bury the cable, what are you going to be 'cleating' the SWA to ?

Ed

 

[flameport]

Run a 6mm T&E cable from the consumer unit & a 4mm earth (smallest size reasonally available) to a point outside, then here terminate them into a outside plastic box (IP65), from there run a 6mm 3-core armoured cable, use the 3rd cable within the SWA as the earth. This is where the additional 4mm earth comes into play.

Or rather than wasting money and time on all that lot, just use 2.5mm SWA from a 20A MCB in the house CU, and connect to a 2 way CU with RCD in the shed.

If you can only connect via an RCD in the house, don't bother with the CU in the shed at all - use metalclad sockets and connect the SWA directly into the first one. Connect the lights via a 5A switched FCU.

 

[gcx51]

Make sure you use a 3 core armored cable and use the 3rd core as an earth.

 

[Spark123]

Doesn't it depend on wether or not you have any extraneous conductive parts in the outbuilding and wether or not the CPC of the cable is adequate to main protective bond the extraneous conductive parts in the building when exporting the earth in a TN-CS? Of course you can always run a main protective bond in if the CPC isn't large enough for that purpose.

 

[gcx51]

Doesn't it depend on wether or not you have any extraneous conductive parts in the outbuilding and wether or not the CPC of the cable is adequate to main protective bond the extraneous conductive parts in the building when exporting the earth in a TN-CS? Of course you can always run a main protective bond in if the CPC isn't large enough for that purpose.

I've always thought that with a PME supply you should fit an earth rod incase of an broken neutral scenario.

I will look in regs book tomorrow to see what it states.

 

[Spark123]

Some stuff here from the 16th edition: http://www.theiet.org/publishing/wiring-regulations/mag/2005/16-elect-inst-outdoors.cfm?type=pdf
I don't think it has changed that much in the 17th, there are more mentions of it in the additional special locations.

 

[planemad]

Here you go

http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html .

If you do not bury the cable, what are you going to be 'cleating' the SWA to ?

Ed

It will be attached to the lower concrete part on my fencing, will sit on a recessed ledge so that it would be safe from garden tools.