Power to cabin

[speedy130]

Hi - we're looking to add a supply to our new log cabin / office in our back garden (about 15m away from the CU). We anticipate it will have 1 PC, a 2kw electric heater, a small fridge and some basic lighting.

We intend to take a 6mm T&E cable from its own connection in the CU in the house (non RCD side), through plastic conduit mounted along the house wall, then buried underground (still in 20mm conduit, under concrete slabs) to some sort of local protection / CU unit in the cabin.

There is already a supply and conduit running above windows & doors along most of the front of the house which simply feeds an outside light at the front door. My main question is, would it be OK to replace that existing cable with the new 6mm T&E and take a connection off it to power the outside light, on its way to the cabin? Or should we replace the existing conduit with something wide enough to take the front door light cable and also the new cable to the cabin?

Would also like some advice about how to terminate the cable and distribute the power when it reaches the cabin?

Cheers

 

[securespark]

Hi - we're looking to add a supply to our new log cabin / office in our back garden (about 15m away from the CU). We anticipate it will have 1 PC, a 2kw electric heater, a small fridge and some basic lighting.

What factors govern your choice of cable?

What is the design current of the circuit?

What protection does the proposed cable have?

Do you realise you cannot lay the cable you propose in the fashion you propose?

If you use the new cable to feed the outside light and the cabin, how are you going to ensure the cabin supply is not dependant upon the outside light being energised?

And how can you fuse down the supply to the outside light while ensuring sufficient capacity for the cabin supply?

How were you proposing to terminate the cable in the cabin?

Look at the bottom of this page for similar posts: they may help.

 

[speedy130]

Hi - we're looking to add a supply to our new log cabin / office in our back garden (about 15m away from the CU). We anticipate it will have 1 PC, a 2kw electric heater, a small fridge and some basic lighting.

What is the design current of the circuit?

What protection does the proposed cable have?

Do you realise you cannot lay the cable you propose in the fashion you propose?

If you use the new cable to feed the outside light and the cabin, how are you going to ensure the cabin supply is not dependant upon the outside light being energised?

And how can you fuse down the supply to the outside light while ensuring sufficient capacity for the cabin supply?

How were you proposing to terminate the cable in the cabin?

OH God - think we'll just pay an electrician then

 

[ericmark]

I am surprised at the amount of twin and earth I see outside. Manufacturers clearly state

Standard: BS6004 Electric cables. PVC insulated, nonarmoured cables for voltages up to and including 450/750V, for electric power, lighting and internal wiring

On the wall outside is not to my mind "internal wiring".

The problem is of course as electricians we have to do as we are told. Be it a regulation or manufacturer we have quite strict guide lines to follow. This means where we come to an installation which does not comply we can't really add to it without correcting at least to the point where we are adding something.

For outside in the main we will always use a black (because it will stand UV better) round (because glands will seal better) cable. The work involved in laying and ducting in the main means if under ground we will use steel wire armoured (SWA) cable. Distributors may use concentric cable but most others stick to SWA.

The manufacturers do give loads of info http://www.batt.co.uk/products for example lists all the major types.

Personally I like a copper earth so would select a 3 core SWA. But as already said you have to design the circuit and supplies to remote buildings do need some thought as to what earthing arrangements. With the paper trail needed today unless really expensive then likely better using an electrician.

 

[speedy130]

Thank you for your helpful reply. I'm rapidly coming to conclusion that unless you're already a qualified sparky, then mains cabling is not a DIY job. Maybe you should change your site logo to diyNOT ....... ?

Seemed like a simple project. Run a cable to a garden shed. My original thought was to just drill through the house wall & take a feed from one of the existing sockets inside the house! We managed to level the site and put together a complete log cabin in a week. Laying a simple cable seems beyond us. Best to get it done right, if only for peace of mind & legal / insurance stuff.

RE:external cabling, we had the house completely rewired about 4 years ago & the feed to the external front door light already had the black conduit pipe in place, and as you suggested they used what was already there.[/u]

 

[streetlighter]

I doubt you would get a 6mm 6242y twin and earth cable through 20mm conduit.
Correct cable to use is SWA what size depends on a few factors and your electrician will be Abel to work this out. Be warned though SWA cable isn't cheap

 

[speedy130]

I doubt you would get a 6mm 6242y twin and earth cable through 20mm conduit.
Correct cable to use is SWA what size depends on a few factors and your electrician will be Abel to work this out. Be warned though SWA cable isn't cheap

Yeah - I checked out the prices on Screwfix

On a different tack... The cabin came supplied with a couple of solar panels (2 x 40W) to charge a 12V battery & run 3 lights. Could a suitable system be devised / upgraded to run a computer, some lights & occasionally a 2kw heater & how do you think the costs of that would compare to running a proper mains supply???

Cheers

 

[OwainDIYer]

On a different tack... The cabin came supplied with a couple of solar panels (2 x 40W) to charge a 12V battery & run 3 lights. Could a suitable system be devised / upgraded to run a computer, some lights & occasionally a 2kw heater & how do you think the costs of that would compare to running a proper mains supply???

Cheers

For computer you could use a laptop. For lights you could use rechargeable lanterns. Bring both back to the house for recharging. Solar panels are unlikely to be cost effective or reliable.

For heat get a bottle gas heater.

 

[speedy130]

Thanks.

Calor gas bottle would be do-able, (although I had wanted a small electric heater on a timer to take the chill out in the mornings), but we would require more power for a proper PC than the laptop.

Sounds like batteries & solar panels is a no-go then.

 

[17thman]

I suggest that you get three quotes from qualified and part p registered electricians, the quotes are free, after all.

You have spent a few quid on a cabin and need to spend a few quid more to make sure you have

1) electrical safety

2) a notification to building control

3) peace of mind

4) convenience of use

5) discussions about future use.

this is not the usual DIY request. Get chatting to some electricians at your home, you will learn a lot and know you have made the correct decision to employ one

 

[speedy130]

Thanks mate - that's exactly what we will do.

I'm sure I could have rigged something up that would have been OK, but like you said, peace of mind & paperwork are worth the extra bit of expense.

Cheers

 

[flameport]

For heat get a bottle gas heater.

DO NOT get a gas heater - they are only suitable for use in well ventilated areas.

Using one in an enclosed space such as a cabin will result in carbon monoxide poisoning.

 

[ban-all-sheds]

Thank you for your helpful reply. I'm rapidly coming to conclusion that unless you're already a qualified sparky, then mains cabling is not a DIY job.

It's only not a DIY job for people who are too stupid or unwilling to accept that they actually have to know what they are doing.

Maybe you should change your site logo to diyNOT ....... ?

No - maybe you should grow some smarts and accept that:

a) There is a lot you need to know to be able to DIY this sort of thing.

b) You don't have that knowledge yet.

c) Unlike DIY carpentery, or painting & decorating, or gardening etc, where it's no biggie if shelves are crooked, doors don't fit, paint has runs in it, wallpaper joins don't match, plants die etc, it is completely unacceptable for electrical work to be done to a lower standard than a professional would do it, because that can get people killed.

Seemed like a simple project.

That's because you have no idea about what's involved in doing it properly.

Run a cable to a garden shed. My original thought was to just drill through the house wall & take a feed from one of the existing sockets inside the house! We managed to level the site and put together a complete log cabin in a week. Laying a simple cable seems beyond us.

I doubt that it is really beyond you, it's just that it is beyond you right now.

• 
  
  
  
• //www.diynot.com/wiki/electrics:mcbtocable
  
  
• http://www.tlc-direct.co.uk/Book/4.3.1.htm (all subsections)
  
  
• http://www.tlc-direct.co.uk/Book/4.3.11.htm
  
  
• http://web.archive.org/web/20080213151445/http://www.kevinboone.com/cableselection_web.pdf
  
  
• http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html
  
  
• http://www.tlc-direct.co.uk/Book/5.3.1.htm
  
  
• //www.diynot.com/wiki/electrics:mcb2
  
  
• http://www.tlc-direct.co.uk/Book/7.13.3.htm
  
  
• http://www.tlc-direct.co.uk/Book/8.1.1.htm
  
  
• //www.diynot.com/wiki/electrics:swa-gland
  
  
• http://electrical.theiet.org/wiring-matters/16/elect-inst-outdoors.cfm?type=pdf
  

RE:external cabling, we had the house completely rewired about 4 years ago & the feed to the external front door light already had the black conduit pipe in place, and as you suggested they used what was already there.[/u]

And what was your most important criterion when you chose an electrician to do that for you?

Because given this:

Be warned though SWA cable isn't cheap

Yeah - I checked out the prices on Screwfix

i.e. that you are shocked at the thought of having to fork out £40-50 for cable to your log cabin (which cost how much, BTW?), and your other question about using solar power to avoid having a proper job done, I suspect that you went for the cheapest you could get, and you know what they say about what you get when you pay peanuts.

 

[speedy130]

.......... well I guess every forum has its "characters"

 

[ban-all-sheds]

And every forum has its share of people turning up, asking what they think is a "simple" question about a "simple" job, and then get all bent out of shape and sarcastic when they find, to their disappointment, that the job is far from simple, and that their decision to do it inevitably raises several questions which they have to be able to answer....