Cable for 4.5kw heater

[mamaji]

Hi,

I'm thinking about installing a 4.5kw sauna heater in an outside. also in the out-house I'll run couple of computers for an office and a heater for winter, and lighting.

I will need to run a armoured supply cable from my main fuse box ( sorry do not know the technical names) to another fuse box in the out house. The cable run will be about 45meters.

What type of fuse woud I need in the out house for the Sauna (20A?) ?

What size cable would I need from the house to oout-house?

Any idea on how much armoured cable would be and how long it would take a compentant electrician to install (trying to work out costs )

Thanks

 

[ban-all-sheds]

What type of fuse woud I need in the out house for the Sauna (20A?) ?

How much current does a 4.6kW load draw?

But why don't you leave that up to your electrician? The rating does not affect the price, and there's no point you buying any of the parts anyway.

What size cable would I need from the house to oout-house?

• //www.diynot.com/wiki/electrics:mcbtocable
  
  
• http://www.tlc-direct.co.uk/Book/4.3.1.htm
  
  
• http://www.tlc-direct.co.uk/Book/4.3.11.htm
  
  
• http://www.tlc-direct.co.uk/Book/5.3.1.htm
  
  
• http://web.archive.org/web/20080213151445/http://www.kevinboone.com/cableselection_web.pdf
  
  
• http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html <- Specify 2-core cable and PVC, even if that is not what you are using or it will make invalid assumptions.
  

But again - it's your electrician who has to decide, as that's Design, and she has to sign certificates to say that she was responsible for it.

Any idea on how much armoured cable would be and how long it would take a compentant electrician to install (trying to work out costs )

Get a few quotes - at least 3. It's unlikely that any of them will be frustrated navvies, and they'll be quite happy for you to dig a 45m long, 45cm deep trench rather than pay them to do it. Once you've dug the trench and prepared the base, laying the cable into it will take practically no time.

Not that you can work out how much a job will cost based on how long it will take to lay a cable.

 

[Taylortwocities]

 

[Maxatoria]

While you have the hole dug lay some waterproof trunking and run some cat 5/6 cables so you can have network/phone access should you need them (you can run normal phones over network cables using modtaps) and most electricians can pull and terminate the stuff

and any money you save will probably be spent on a digger unless you have lovely fine sandy soil

 

[flameport]

Any idea on how much armoured cable would be and how long it would take a compentant electrician to install (trying to work out costs )

The cable will probably be in the £200 to £250 range.
Time - unknown without looking.

For the whole job, expect to pay at least £1000. Could easily be a lot more than that.

 

[mamaji]

Maxatoria - thanks. I was thinking about getting a seperate phone line with broadband in the outside, did not consider your option - this could save me some monthly ££

Fameport - thanks. Did not expect it would cost that much. I understand that how long the job takes is an unknown and hence a guess at the cost.

What size cable would be suitable? The reason I ask is that when I get some quotes in and the electrician says "x" mm and this is WAY off compared to what you guys have suggested. Then I have some understanding of thier knowledge / experience.

Cheers.

 

[Maxatoria]

You need to consider that you lose a certain number of volts per meter and you need to have enough of them to be able to use your equipment and the smaller the size of cable the more your lose per meter so a fatter cable is better generally and if you decide to slap even more gear you wont have to dig up the old cable and replace it so its best to have a chat with a good electrician to work out what your future demands may be so that you can get sorted out once as i doubt you fancy spending good money on hiring a digger so you can drop some slightly bigger cable in the hole

 

[ban-all-sheds]

What size cable would be suitable?

• //www.diynot.com/wiki/electrics:mcbtocable
  
  
• http://www.tlc-direct.co.uk/Book/4.3.1.htm
  
  
• http://www.tlc-direct.co.uk/Book/4.3.11.htm
  
  
• http://www.tlc-direct.co.uk/Book/5.3.1.htm
  
  
• http://web.archive.org/web/20080213151445/http://www.kevinboone.com/cableselection_web.pdf
  
  
• http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html <- Specify 2-core cable and PVC, even if that is not what you are using or it will make invalid assumptions.
  

 

[mamaji]

Thanks, the link below gave me some indication - not that I understand all the values to input !!... but I can at least ask the right questions to the "expert" that will quote me.

[*] http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html <- Specify 2-core cable and PVC, even if that is not what you are using or it will make invalid assumptions.

 

[ban-all-sheds]

Thanks, the link below gave me some indication - not that I understand all the values to input.

So you probably won't be well equipped to start arguing with electricians over their sizing...

Don't know why you're expecting them to try to con you - the tiny amount of extra money they would make from the markup on a larger cable wouldn't be worth the aggro of lugging a heavier reel to and from the van - a 50m reel of 10mm² SWA is already going to weigh around 45kg....

 

[mamaji]

Thanks, the link below gave me some indication - not that I understand all the values to input.

So you probably won't be well equipped to start arguing with electricians over their sizing...

I don't want to argue with a professional! - What I would like to do is ask relevant questions.

Don't know why you're expecting them to try to con you - the tiny amount of extra money they would make from the markup on a larger cable wouldn't be worth the aggro of lugging a heavier reel to and from the van - a 50m reel of 10mm² SWA is already going to weigh around 45kg....

Unfortunately, there are people who can talk the talk but not deliver. I would prefer to figure this out in the early stages, I do not want to put my family in danger or do I want a time consuming issues after by reporting to the authorities.

The info on the wieght of the cable is very useful and can understand that logic - as a layman I can now start to understand some of the costs, what's involved, why the "expert" may recommend certain things. - that's why I use such forums.