110 metre submain for 4/5 bed new build?

[BillyH]

What size swa would be needed for a 4/5 bed new build property submain burried direct in ground?

 

[Plonker 3]

Do the calculations for Volt drop, design current etc and you will have your cable size.

 

[BillyH]

table 4D4B HAS 3 columns r, x and z. Which column do i use?

 

[telectrix]

clue....... bigger than 25mm.

 

[Octopus]

Astonishing.

Do you think you're ready for such jobs?

 

[telectrix]

easier to use osg table 6D2.

 

[Plonker 3]

table 4D4B HAS 3 columns r, x and z. Which column do i use?

Google can be very helpful sometimes.

 

[telectrix]

and if there are 4/5 en-suite showers with 4/5 teenage daughters, then it's do the calcs. and X by 3.

 

[BillyH]

Astonishing.

Do you think you're ready for such jobs?

Been a long day . Out the house a 5.30 this morning and just got in.Don,t really need "help" like this. I know i should be able to do this in my sleep ( kinda feels like i am) but a little guidance might be more constructive

 

[Octopus]

Been a long day . Out the house a 5.30 this morning and just got in.Don,t really need "help" like this. I know i should be able to do this in my sleep ( kinda feels like i am) but a little guidance might be more constructive

Maybe your post could have been worded in such a way to encourage people to help you.

 

[Amp David]

Have never yet specced any cable size going off how many bedrooms a house is to have.

80 amp cut out lets say 50mm

 

[telectrix]

looking more at VD, i'd be considering 70mm.

 

[BillyH]

Maybe your post could have been worded in such a way to encourage people to help you.

Sorry,should've been a bit clearer. I had an answer phone message on the way home asking for this info so just wanted a quick answer so i could knock off.

 

[Eco Chap]

That's a very vague design...

Max demand = 4/5 bedroom house?

Don't know if that's accepted under bs7671. Any clues on run load ect

 

[Eco Chap]

looking more at VD, i'd be considering 70mm.

Hell go with a 90mm just incase!

 

[SPARTYKUS]

Hell go with a 90mm just incase!

3 core - need an extra for bondings

 

[Eco Chap]

3 core - need an extra for bondings

Now your just making assumptions

 

[BillyH]

Sorry for the vague info, i will explain more.The supply is for a 4 or maybe a 5 bed house (100A). Allowing for a 5% vd the cable size would be 50mm.

0.94x110x100/1000 = 10.34

Am i close

 

[telectrix]

close, but VD for lighting is 3%, so i'd err on the side of caution. better to install a slightly oversized cable than have to dig out and replace an undersised one.

i got 70mm based on 80A demand.

5.6V drop.

 

[sedgy34]

my apprentice wouldnt ask that question

 

[SPARTYKUS]

Thats a big run. And a big cable. Will need jacks and strong blokes!

 

[BillyH]

I just got an email from the guy. This is the only info i have. I know nothing about whats on site whatsoever so can't comment further .It reads as follows;


I need to put in 5 supplies. One each for the 3 units - these will all be say 3 bed, and no electric heating or showers. They each have a cable run of 75 metres.
One run needs to go to the house - this will be about 110metres, and it will be a 4/5bed house.
The other one needs to go to the sewage treatment plant, which is again about 120 metres, but only needs to run a 200 Watt pump.
Everything single phase.

Why would this be preferable to getting the board in to give new supplies?

 

[Amp David]

close, but VD for lighting is 3%, so i'd err on the side of caution. better to install a slightly oversized cable than have to dig out and replace an undersised one.

i got 70mm based on 80A demand.

5.6V drop.

Just a guess at 50mm, close though damn!!!LOL

 

[sedgy34]

I just got an email from the guy. This is the only info i have. I know nothing about whats on site whatsoever so can't comment further .It reads as follows;


I need to put in 5 supplies. One each for the 3 units - these will all be say 3 bed, and no electric heating or showers. They each have a cable run of 75 metres.
One run needs to go to the house - this will be about 110metres, and it will be a 4/5bed house.
The other one needs to go to the sewage treatment plant, which is again about 120 metres, but only needs to run a 200 Watt pump.
Everything single phase.

Why would this be preferable to getting the board in to give new supplies?

you need a site meeting mate and deisgn it correctly, also submains are cheaper than paying the dno

 

[BillyH]

my apprentice wouldnt ask that question

Nor mine. Its been over thirty years since i did my time so i think i'm entitled to be be a bit rusty,forgetful,senile or whatever.I'm not proud of asking such basic questions but if you're not sure its best to ask, is it not?

 

[Amp David]

This will help you out in times of rustyness.

Cable-Mate

 

[telectrix]

we all get a brain fart now and then. best to be sure before doing than make a cock -up

- - - Updated - - -

This will help you out in times of rustyness.

Cable-Mate

or AEI cable finder on line, it's free.

 

[topquark]

table 4D4B HAS 3 columns r, x and z. Which column do i use?

The r, x and z colums are values for resistance and corrections when taking into account reactance and impedance respectively. Only need worry about reactance and impedance over about 16mm.

 

[UKMeterman]

For the big cables, ask the DNO for a quote if you agree to dig the trench for them, or use a contractor they normally use such as Murphy or similar.