Electric to Garden Shed

[ShayneColbert]

Hi,

I am building a shed at the bottom of my garden that is about 80m away from the house. I plan on running electricity out to the shed so I can run my power tools whilst building it. And to use once built. Would it be ok 2 link several 13A garden extension leads together, 3 x 30m ones. Or would the voltage drop be too high for this to work.
If so does anyone know what size cable I should be looking for to run out there. 3000W should be plenty of power for everything that I need to run now and in the future.

Thanks for any advice.

 

[ban-all-sheds]

Would it be ok 2 link several 13A garden extension leads together, 3 x 30m ones.

Don't be ridiculous.

• 
  
  
  
• //www.diynot.com/wiki/Electrics:books
  
  
• //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/20070327014113/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.
  
  
• 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
  
  
• //www.diynot.com/wiki/Electrics:Part-P
  
  The references above which are in italics are out of date. The principles are still valid, and you can absolutely learn valid things from them, but you will need to refer to the latest edition of the Wiring Regulations to get the correct data.

 

[skotl]

Would it be ok 2 link several 13A garden extension leads together, 3 x 30m ones.

Don't be ridiculous.

((The usual list of war-and-peace / copy-and-paste unhelpful nonsense from B-A-S))

Any chance that, instead of simply insulting the OP, you could help guide them by specifying what the issues may be with his approach? Or is your intention simply to once again send a new poster packing and repel him from this forum?

 

[ban-all-sheds]

So you don't think that connecting a bunch of extension leads together is ridiculous?

And you don't think that it would be helpful to the OP to learn how to do the job he wants to do? How would you suggest he goes about designing and installing this if he doesn't know how?

 

[ShayneColbert]

So I've just been researching and have come to the conclusion that 6mm2 cable should do the job. I'm going to get armored 3 core. The total length of the run should be about 90m all the way to the switch box in the house. 13A will be sufficient for what I intend to use out there. I used a voltage drop calculator which worked out at 3.73%. Does this seem an acceptable voltage drop for things such as TV's and PC's.

So why is the extension leads ridiculous. I'm guessing that the cable is probably only around 1.5mm2 but it was only going to be a temporary solution to run 1 500w light. I don't need the power tools yet. I'm only leveling my excavation at the moment. Am I missing something else.

Proper cable was going to be put in when the shed was done. I can pick up the extension leads on the way home from work but will have to wait far longer for a proper cable run. I'm fed up of working in the dark with only my dim head torch. It's already dark by the time I'm home from work.

 

[ban-all-sheds]

13A will be sufficient for what I intend to use out there.

And if it ever becomes insufficient will you be OK with digging another 80m trench?

I used a voltage drop calculator which worked out at 3.73%.

Does this seem an acceptable voltage drop for things such as TV's and PC's.

They'll be fine, but that drop is over the limit for lighting.

So why is the extension leads ridiculous.

I plan on running electricity out to the shed so I can run my power tools whilst building it. And to use once built.

So your suggestion of daisy chaining several extension leads was a suggestion that that would be how you supplied the shed on a permanent basis.

Do you really think that a permanent supply to an outbuilding should be via multiple extension leads plugged together and trailing over the garden?

I'm guessing that the cable is probably only around 1.5mm2 but it was only going to be a temporary solution to run 1 500w light.

It would be OK for that, but I'd worry about how waterproof the connections would be. You could get 100m of 2.5mm² Arctic cable and make your own with no intermediate joins.

 

[ShayneColbert]

So why is the extension leads ridiculous.

I plan on running electricity out to the shed so I can run my power tools whilst building it. And to use once built.

So your suggestion of daisy chaining several extension leads was a suggestion that that would be how you supplied the shed on a permanent basis.

Sorry should probably been a bit more clear on that. The missus would never allow that to be a permanent fixture across her garden. So what is the tolerable voltage drop for lighting. And could you use led lighting instead as that's what alot of tvs use and if 3.73% is acceptable to them then surely they should be ok.

 

[ban-all-sheds]

Sorry should probably been a bit more clear on that.

OK.

Hope you see why it looked like a suggestion for the permanent installation, and that it would have been a ridiculous suggestion.

So what is the tolerable voltage drop for lighting

The regs say 3%. But if you use ELV lighting you'd get away with a bit more - SMPSUs (which is what ELV lighting "electronic transformers" are) can cope with wide variations in supply - take a look at the data plate on the back of a TV, or a laptop charger.

But why sail so close to the wind? 80m is a heck of thing to have to re-do if 6mm² becomes inadequate - I'd put in 10 or 16mm² for insurance.

 

[bernardgreen]

So you don't think that connecting a bunch of extension leads together is ridiculous?

To a very knowledgeable person like you it may sound ridiculous, I know the use of linked extension is not satisfactory and if ( as has happened ) someone asked me about linking them I would explain why it should not happen. I would see them as un-informed and therefor in need of advice and help and certainly not worthy of ridicule.

 

[JohnW2]

So what is the tolerable voltage drop for lighting

The regs say 3%. But if you use ELV lighting you'd get away with a bit more - SMPSUs (which is what ELV lighting "electronic transformers" are) can cope with wide variations in supply...

Indeed with a good few SMPSUs, one could probably 'get away with' a 50% voltage drop!

However, if one assumes that all/most LV lighting is designed to be able to function at the lowest permissible supply voltage, most people would 'get away with' much more than 3% VD, even for LV lighting. Even if (unusual) their normal supply voltage were only 230V, then it would require a 6% VD before that got down to the minimum permissible supply voltage. If they supply was usually nearer 240V (much more common) that would rise to around 10%.

Kind Regards, John

 

[deadshort]

Would it be ok 2 link several 13A garden extension leads together, 3 x 30m ones.

Don't be ridiculous.

((The usual list of war-and-peace / copy-and-paste unhelpful nonsense from B-A-S))

Any chance that, instead of simply insulting the OP, you could help guide them by specifying what the issues may be with his approach? Or is your intention simply to once again send a new poster packing and repel him from this forum?

Go on Skot , show us how its done - without 'War and Peace'


Kind regards,

DS

 

[ban-all-sheds]

To a very knowledgeable person like you it may sound ridiculous, I know the use of linked extension is not satisfactory and if ( as has happened ) someone asked me about linking them I would explain why it should not happen. I would see them as un-informed and therefor in need of advice and help and certainly not worthy of ridicule.

1) IMO someone would only need a modicum of common sense to know that stringing a bunch of extension leads across the garden as a permanent supply to an outbuilding was a ridiculous idea, not a great deal of knowledge.

2) I wasn't ridiculing the OP.

 

[JohnW2]

Go on Skot , show us how its done - without 'War and Peace'

I agree that coming up with a constructive alternative is not necessarily easy, but I'm pretty sure that few, if any, of the people to whom they are directed will look at (let alone 'study') one, let alone all, of the links in the 'War and Peace' list - so there has to be something better (and more likely to be be at least partially successful in terms of what BAS is trying to achieve).

Kind Regards, John

 

[EFLImpudence]

There is too much to write to explain everything necessary and/or required for outdoor installations.

It would need a step by step instruction manual.
If anyone wants to write the 'War and Peace' for this then carry on.
Until then, employing an electrician to, at least, supervise is the only answer.

 

[JohnW2]

There is too much to write to explain everything necessary and/or required for outdoor installations. ... It would need a step by step instruction manual. ... If anyone wants to write the 'War and Peace' for this then carry on. ... Until then, employing an electrician to, at least, supervise is the only answer.

Exactly. In cases like this, that is often the only sensible/practical advice - and, if put like that, might conceivably be heeded (much more likely, IMO, than that the 'War and Peace' links list is every likely to achieve anything much'!)

Kind Regards, John