outhouse electrics

[wysiwyg19620]

First i would like to say hi to everyone, this is my first post so here goes.
In my outhouse i have a cu with just 2 mcbs 16 and 6 amp and main switch and no rcd. this is fed from the main cu in the house via a 20amp mcb on the rccb side. The main cu is above my front door so the swa comes through the wall and around the ouside of my house to the back and then on tension cable for 8 feet then into my outhouse consmer unit. The cable is swa 2.5mm. i would like to put power into my shed which is about 10 feet away from my outhouse, what would be the best way of doing this? I thought perhaps i could take a feed from the outhouse consumer unit into my shed into an rcd controlled consumer unit but i am a bit concerned over the 2.5 cable not being big enough for the total run of about 35 metres.
The earthing arrangements for the outhouse which is about 4 feet from the house is via the main consumer unit and i know i need a stake for the shed. The cu in the outhouse is supplying one light via the 6 amp mcb and two sockets for a couple of freezers.
I would appreciate any constructive thoughts in this.

 

[Taylortwocities]

First question.

This shed, what will you run in there
MIG welder? Lathe?

or just lights and a socket for light use?

The concern is not the length of the run itself, its a combination of the length of the run and the LOAD.

Note - before you go and do anything - this work is notifiable so you may need to get a spark in to do it for you.
See the WIKI for details.

 

[wysiwyg19620]

no lathe or welder, just lights and general tools, ie bench drill 400w, router, sander etc
hoover, radio cannot evisage running above 2000w.

 

[Taylortwocities]

Assuming the TOTAL load of the 35metre run is 2KW then 2.5mm² SWA with XLPE should be adequate.

You could install a 13A fused connection unit from the 16A MCB in the outhouse fusebox and run a length of SWA from there - you'll be limited to 13amps. Sould be plenty as 2KW is around 8.5A.

You/an electrician would need to wire up the shed. The lighting would need to be fused down as needed.

Why would you need an RCD in the shed? I think you already said that the original feed from the house comes from the RCD side of the CU?
There's no point having two 30mA RCDs in tandem.

How will you run the add-on SWA cable?

If you are doing it, all of this must be notified to the local authority before work starts as they will want to inspect at various stages.
Also the work will have to be installed, tested and certified to meet BS7671 so I hope you have all of the necessary calibrated test equipment (Continuity tester, Insulation tester, RCD tester)

 

[wysiwyg19620]

i would strip back the armour, terminate it in an outside junction box leaving the inner to connect to the cu and the same to the shed.

 

[RF Lighting]

How do you earth the armour if you do that though?

 

[wysiwyg19620]

i would earth the armour via the earth tag on the termination gland and run the earth cable to the earth bar in the outhouse consumer unit.