what do I need at the shed end?

[12promises]

hi,
I have just had my old shed knocked down and will have a new one soon.
There is an underground cable from the house cu to the shed already so what do I need to buy hardware wise to put in a double socket to run a small chest freezer and a light?
Thanks.

 

[PrenticeBoyofDerry]

Firstly you will need to confirm the existing cable is suitable for continued service and also suitably sized for the load demands and the distance it runs from house CU and Shed.

So what type of cable is it?
How is it routed in the ground, depth of cable, in containment?
What Cross Section is the cable?
What is the distance the cable runs?
Have you tested the continuity and insulation resistance of the cable?
What earthing arrangements do you have/
What is the Ze at the board?

 

[ericmark]

A double socket and a switched fused connection unit (FCU) as light switch and a light.

I am sure you already know that?

What you really need is to look at the supply with some exceptions freezers use a lot of power to start and if the volt drop becomes excessive then the overload tends to trip far more often than designed and the unit fails. Since often built into the motor that means new freezer.

As I say there are exceptions some now use three phase motors and an inverter these don't take anywhere near the start current of the older units but to date only seen with upright units and since upright units of that quality have auto de-frost they have to be used where the ambulant temperature is more than 10°C.

So length of run and size of cable is important for freezer use. No problem with the lawn mower but with freezer it's important. In the main we measure the loop impedance or prospective short circuit current. Also any discharge lighting may have a problem with volt drop.

So to keep within the 6.9 volts for lighting with a 13A supply using 2.5mm² cable the maximum length is around 32 meters. PSCC should be around the 260A mark for the volt drop to be around the 6.9 volt mark.

I have worked on a 13A supply which means a 13A fuse in a FCU in house and also a 3A fuse in a FCU in shed these will also have a volt drop.

You will note most freezers have a warning do not use with extension leads this is because of the volt drop. Where I live with incoming mains at 240 volts likely no problem anyway. But further down the street so further from the main transformer it could be. Supply is 230 volt +10% to -6% so 216.2 ~ 253 volts if your already on the low side it may be a problem but if on the high side then no problem.

 

[Taylortwocities]

A double socket and a switched fused connection unit (FCU) as light switch and a light.

I am sure you already know that?

PLUS the socket must be protected by a 30mA RCD, either at the shed end , or at the house end.

As outlined above. What you need is dictated by what you have got.

 

[ban-all-sheds]

Firstly you will need to confirm the existing cable is suitable for continued service and also suitably sized for the load demands and the distance it runs from house CU and Shed.

So what type of cable is it?
How is it routed in the ground, depth of cable, in containment?
What Cross Section is the cable?
What is the distance the cable runs?
Have you tested the continuity and insulation resistance of the cable?
What earthing arrangements do you have/
What is the Ze at the board?

Also...

run a small chest freezer

Are you aware that many (most) freezers don't work if they are somewhere cold, and even ones which work at lower temperatures than most may not be happy down at what you'll see in winter? Is the shed insulated and heated?