Electrified Shed

[jm317]

Hi

I have a query before I approach my local electrician & local CC:

I'd like to run just a small 100L chest freezer in my shed 20 meters from the Tenby consumer unit in the house (all Sockets are on RCDs). The freezer (150W) draws a couple of amps & 750 peak watts when the compressor is running... averages 500W/24hrs peak.

What materials would you recommend to complete this job.

Many thanks

JM

 

[RF Lighting]

Why not ask your electrician when you approach him?

 

[jm317]

I'm sure there is more than one way to do this & I like to be informed.

JM

 

[oharaf]

You're right there is more than one way.

First way is;

The Right Way - Using a registered sparky who can cert & notify

The Wrong Way - Doing it yourself when you haven't got a clue.

 

[jm317]

thanks very helpful.

 

[sparkyspike]

It really depends on the situation. Normally SWA cable will be used, running from the main CU in the house and terminating in a 'garage consumer unit' which will give you power for the freezer and for a light. Otherwise you can terminate the cable into a metalclad socket or fcu if you just want to run a freezer.

The SWA can be run under ground, or overhead using catenary wire. Your electrician will probably select 2.5mm 3-core SWA.

There may be other things to consider, such as exporting earths etc., but your electrician will worry about that.

 

[ericmark]

Taking power to a shed has been covered in Wiring Matters from IET. See Electrical installations outdoors: a supply to a detached outbuilding (243 k) this was published in 2005 under old regulations but not too much has changed.
I will guess much of what is said will go right over your head, but maybe I am wrong. With lighting being included you are only allowed 3% volt drop now and you will need to calculate this as it was 4% at time of the publication. Also you will likely need RCD protection now.
You will see how consideration is given to TT and TN-C-S supplies and to make measurements to work out which will need an earth loop impedance tester also an RCD tester and a low ohm ohmmeter and a high voltage ohmmeter will be required these will cost around £750 plus the £100 plus vat you will need to pay the LABC so in real terms it is not a DIY job.
I hope with what I have said you will understand why.

 

[TicklyT]

One part of the materials list for the job an electrician will probably be more than happy for you to supply is a trench to put the cable in.

You will need to discuss the job with your electrician first to save you from buying the wrong size trench, or installing it in the wrong place.

Generally when buying trenches for cable, you will need to look out for one about 600mm deep, with a sand lining at the bottom and a plastic warning tape to lay over the cable.

 

[bernardgreen]

Generally when buying trenches for cable, you will need to look out for one about 600mm deep, with a sand lining at the bottom and a plastic warning tape to lay over the cable.

And remember not all trenches come with the necessary back fill material

 

[TicklyT]

We tried using some trenches imported from Poland a while back. Whilst they looked like a good deal, the installation instructions were almost incomprehensible.

 

[bernardgreen]

They can however supply components for a good overhead line using electricity poles. The instructions show how you crane them into place.

 

[stephenf8542]

E-bay do a good line in trenches but watch out you dont get an imperial one instead of metric

 

[bernardgreen]

Bit risky on E-bay. can get you in deep trouble if you are not carefull.

Sold as being 50 yards by 6 foot by 2 foot. When it arrived it was 2 foot wide and 6 foot long........

 

[sparkyspike]

A trench is for the French. Poles prefer poles....

 

[oharaf]

My customer at the weekend had brought the wrong depth trench

It was only 150mm deep, whilst i cracked on he went and bought another one, that was the wrong depth as well

So he went to get another whilst I ate his biscuits