How to connect electric to outbuilding

[Talay]

I have an outbuilding which I would like to bring into the 21st century with electric and all that. At present is is little more than walls, a window and a roof. It is however dry and weatherproof.

Ideally, I'd like to be able to run a bank of washing machines and driers in it. I am not talking 3 phase but regular domestic stuff. Perhaps a maximum of 6 washers and 6 dryers, some lights and possibly a bit of heating.

I have a 100A main fuse and a split consumer unit with Economy 7.

I'm not suggesting I do this myself but I would like to understand what is involved, what wiring I need internally and what I need as it does through the garden for about 10 metres to this outbuilding.

I do have some 16mm cable going most of the way already and wonder whether I (not me !) could cut a new cable into this supply and save a complete new installation. At present this 16mm cable supplies only a water heater unit with a maximum draw of 13.2kw.

All suggestions most welcome.

 

[Taylortwocities]

You are going to need a very competent electrician to do some careful load demand and volt drop calculations.

"6 washers and 6 dryers, some lights and possibly a bit of heating" will be a substantial load. The cable to the outbuilding will have to be big enough, or you will not have enough volts at the end to work the dryers properly under high load conditions.

Also, the load in the existing house will need to be assessed to see if 100amps is enough.

 

[mfarrow]

Perhaps a maximum of 6 washers and 6 dryers, some lights and possibly a bit of heating.

That's a lot of power if you're running on electric alone. I'd seriously consider a gas run for the dryers and possibly heating as well.

I have a 100A main fuse and a split consumer unit with Economy 7.

That's a good start, and means for recommended discrimination you can have a 63A fuse supplying your outbuilding, or a suitable set MCCB.

I'm not suggesting I do this myself but I would like to understand what is involved, what wiring I need internally and what I need as it does through the garden for about 10 metres to this outbuilding.

You need an electrician and a proper measurement of the run from consumer unit to the outbuilding. Personally, SWA from outside of house to outside of outbuilding then singles or T&E internally from external weatherproof boxes.

I do have some 16mm cable going most of the way. At present this 16mm cable supplies only a water heater unit with a maximum draw of 13.2kw.

That's 57A, and assuming it's a thermostatically controlled single element, you won't get much more from your cable, so you'll need to dig and put in afresh.

Assuming you're using this for business and need 2x 3kW space heaters, then the load after diversity will be over 100A, which your existing installation won't support. Using gas fired dryers and heating may reduce this to just within 63A, but you need to have someone assess how this load will conflict with your other water heater unit.

 

[flameport]

I'm not suggesting I do this myself but I would like to understand what is involved

What is involved is getting a new, totally separate supply installed.

The existing supply to your property is NOT adequate for the suggested additional loads.

If you intend to use these washers for business purposes, buying domestic models will be cheap to start with, but very expensive long term, as they simply will not last being used all day.
You will also find any warranty is voided by using them outside a domestic situation.

 

[ban-all-sheds]

You'll also need to sort out connecting to the water supply, and sewer.

That will almost certainly not be allowed under your agreement as a domestic user.

Building Regulations approval will be needed for the services, and change of use, and there may be planning permission required.

 

[ricicle]

Sounds like it might turn into a place of work so The Electricity at Work Regulations:1989 will apply. You will need a competant person to carry out the work and also regular electrical inspections on the 'laundry' will be required.
Personally it sounds like a non-runner from the off.

 

[bernardgreen]

As Ban said you need to check that what you are planning is permited under planning laws. If the building has not reviously been used for commercial use you will probably need to obtain a "change of use" permission from the council planning department. Anything more than 2 washing machines will be seen as commercial activity ( unless you have a very large family ).

 

[flameport]

If, as seems obvious, you want to set up a laundry business, find a suitable commercial building to do it in. One which will already have the required electricity, gas, water and drainage.

Dryers will need to be gas ones, unless you like throwing vast amounts of money away.
Another handy hint - you cannot run 6 gas tumble dryers from a domestic gas meter.

 

[TheKeymeister]

You'd also need to contact the DNO or supplier as your supply would probably need upgrading and would become a non-domestic supply rather than domestic.