Cable sizing

[RBS]

Need a cable to run approx 100m from incoming supply to a new build house,cable will be buried under ground what is the mimimum size cable that could be used to make it comply with the regs? Copper/aluminium? Thanks

 

[plugsandsparks]

Probably better to ask EON

 

[trev]

That's like asking how long is a piece of string mate. More info is needed.

 

[Guitarist]

No offence, but if you are asking this question on a forum then maybe you need professional help on-site.

 

[Jimmyb]

depends on design current for starter

 

[macca_31]

your power provider will be able to determine what size cable you need, again u shouldnt be running this off your own back etc

 

[lurch]

Need a cable to run approx 100m from incoming supply to a new build house,cable will be buried under ground what is the mimimum size cable that could be used to make it comply with the regs? Copper/aluminium? Thanks

why would you wanna do that?

 

[Adam W]

"A new build house" is a bit vague. Firstly how big is it? 8 bedroom? Wendy?
As mentioned there are too many variables, hence there being no '1 size fits all' supply cable to any property that falls under the heading of 'house'.
You'd need to calculate maximum demand, then the DNO will hook you up if they're satisfied you've wired the place up right.

 

[RBS]

Barn has been dropped and permission has been granted to build a 4 bedroom house,and the nearest point of supply is approx 100m away, around 6k to have cable laid by supplier so was thinking surely that it would be cheaper to buy cable and lay it and let them connect up????

 

[trev]

If you're lucky the DNO will accept that but I wouldn't hold my breath for that if I were you.
It's their toy and you can't play with it usually

 

[Guitarist]

Again, with the greatest respect, you are trying to lay a cable the DNO have quoted you 6k for and you are asking on a public forum how to do it to save some cash. "out of depth" comes to mind.

 

[GLENNSPARK]

If you're lucky the DNO will accept that but I wouldn't hold my breath for that if I were you.
It's their toy and you can't play with it usually

exactly Trev....why would they risk losing any profit opportunity here.....and you can be sure that they will have vectored that into the costs......

 

[trev]

Not so much the profit opportunity Glenn. From a "doing it right" standpoint, how would the DNO be sure that there's not half a million tape joints in the buried cable? How would they be sure that the correct cable has been installed all the way along the run?

To me it comes back to the old part p thing, would you sign off a domestic install if you wern't involved 100%? and there's no difference here in my world

 

[GLENNSPARK]

Not so much the profit opportunity Glenn. From a "doing it right" standpoint, how would the DNO be sure that there's not half a million tape joints in the buried cable? How would they be sure that the correct cable has been installed all the way along the run?

To me it comes back to the old part p thing, would you sign off a domestic install if you wern't involved 100%? and there's no difference here in my world

ok Trev...i can understand how the DNO would want to be sure of the job being done right.....so working on this basis....how is it that they often shirk their responsibilities when it comes to maintaining earthing arrangements that they have supplied...and are being used by consumers installations...?....and as regards to not signing off work that you havn`t been involved in ...at 1st, 2nd and ins and test.....well those that get up to such stuff leave themselves wide open dont they..lol...

 

[trev]

ok Trev...i can understand how the DNO would want to be sure of the job being done right.....so working on this basis....how is it that they often shirk their responsibilities when it comes to maintaining earthing arrangements that they have supplied...and are being used by consumers installations...?

Damn you Glenn, you just pee'd on my fireworks
Bloody good point there mate I should have thought of that

 

[trev]

Hoist by my own pettard

 

[GLENNSPARK]

Damn you Glenn, you just pee'd on my fireworks
Bloody good point there mate I should have thought of that

well i can assure you that wasn`t the intention Trev:angel_smile: but i dont see why if they demand one thing....they cant see to the other n all.....its like movin the goalposts or summat innit....

 

[trev]

I know it wasn't the intention Glenn but you got me fair and square and you're right about them moving the goalposts as and when it suits them.
What was that line from Father Ted a few years back?
Oh yeah I remember now, Shower of B..........

 

[GLENNSPARK]

you are of course quite righ in saying that this work needs to be carried out in a correct manner though Trev....and i would also be inclined to discourage a `do it yourself` approach....

 

[plugsandsparks]

The only way i could think of to reduce the cost is to dig the trench yourself, they might accept that bit but if you want a proper metered supply with a bill and all, i.e. a property you can sell then i expect the power company will want to splice into their supply and provide the appropriate cable and fuse for the new property. It is their right

 

[Engineer54]

For them to approve a supply run like this, they would probably want the cable run in a concrete covered duct at 600mm depth, and would want to inspect it before back-filling!! Also if you were supplying the cable as well, would probably want to be present during the cable pulling, (all at your cost)!! lol!!

 

[Geordie Spark]

I worked on a new build 4 bed detached a couple of years ago. It was set back about 20 metres from the road and one trench was dug from the street to the house.

Into that trench went the gas supply - yellow Alkathene pipe run inside yellow plastic duct, water supply - blue Alkathene pipe and the electricity supply - split concentric cable.

All three services in the same 700mm deep trench resting on and surrounded by pea gravel before being back filled.

 

[a1guvner]

The only contestable element would be ground works or containment within your boundry

 

[Amp David]

Barn has been dropped and permission has been granted to build a 4 bedroom house,and the nearest point of supply is approx 100m away, around 6k to have cable laid by supplier so was thinking surely that it would be cheaper to buy cable and lay it and let them connect up????

If only it was a simple as that.

The supply you want to utilise, is it the old one for the barn or for something else.

 

[ABerry82]

i have been asked to install a garage unit in a outbuilding they wanted a couple of sockets and lights and i think i allowed about 20A total output. what size cable do you think bearing in mind its a 90 meter run in a trench from house to out building.

 

[DPG]

get ready for it..... daz

 

[Engineer54]

I worked on a new build 4 bed detached a couple of years ago. It was set back about 20 metres from the road and one trench was dug from the street to the house.

Into that trench went the gas supply - yellow Alkathene pipe run inside yellow plastic duct, water supply - blue Alkathene pipe and the electricity supply - split concentric cable.

All three services in the same 700mm deep trench resting on and surrounded by pea gravel before being back filled.

Pea gravel is not suitable to surround and compact around any type of direct buried cable, especially not with non-armoured concentric cable, ...Full Stop!! Cable in a suitable duct with a compacted surround of pea gravel you can get away with!!!... Cables should preferably always be laid on a soft sand bed and surrounded by compacted soft sand. At the very least, a bed of sifted soil and sifted compacted soil backfill....

 

[Geordie Spark]

Pea gravel is not suitable to surround and compact around any type of direct buried cable, especially not with non-armoured concentric cable, ...Full Stop!! Cable in a suitable duct with a compacted surround of pea gravel you can get away with!!!... Cables should preferably always be laid on a soft sand bed and surrounded by compacted soft sand. At the very least, a bed of sifted soil and sifted compacted soil backfill....

Be that as it may, that's what the contractors working for the DNO used !!

The trench was dug by the bloke who was building the house - it was a self-build - for himself, the contractor working for the gas supplier laid the gas pipe in it, the contractor working for the water supplier laid the water pipe in it, then the contractor working for the DNO laid the cable in it & covered the whole lot with pea gravel which they brought on a lorry. There was no sand - soft or otherwise - anywhere in sight.

After that, the bloke who dug the trench back filled it.

I have to say I was a bit dubious about the whole thing, but who am I to argue with the experts ??

In the end, my contribution to the project - which was the wiring, plumbing & heating installation - was all up to scratch, and that's all I was worried about.