Discuss 110 metre submain for 4/5 bed new build? in the Electrical Forum area at ElectriciansForums.net

Status
Not open for further replies.
B

BillyH

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

Plonker 3

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

BillyH

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

Murdoch

Regular EF Member
Messages
26,648
Location
Woking
Astonishing.

Do you think you're ready for such jobs?
 

telectrix

Disrespected Scouser
Electrician's Arms
Trainee Access
Messages
63,525
Location
cheshire/staffordshire
and if there are 4/5 en-suite showers with 4/5 teenage daughters, then it's do the calcs. and X by 3.
 
OP
B

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
 

Murdoch

Regular EF Member
Messages
26,648
Location
Woking
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

Mentor
Electrician's Arms
Trainee Access
Messages
5,113
Location
Glossop
Have never yet specced any cable size going off how many bedrooms a house is to have.

80 amp cut out lets say 50mm
 
OP
B

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.
 
OP
B

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

Disrespected Scouser
Electrician's Arms
Trainee Access
Messages
63,525
Location
cheshire/staffordshire
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.
 
OP
B

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

Mentor
Electrician's Arms
Trainee Access
Messages
5,113
Location
Glossop
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

Solar Guru
Messages
3,028
Location
In a recession
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
 
OP
B

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?
 

topquark

Electricians Arms Member
Mentor
Electrician's Arms
Trainee Access
Messages
3,377
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

Electrician's Arms
Messages
810
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.
 
Status
Not open for further replies.

Permanent unswitched live colour?

  • Brown

    Votes: 64 66.0%
  • Black

    Votes: 33 34.0%

Electrician Talk

Electrical Forum

Welcome to the Electrical Forum at ElectriciansForums.net. The friendliest electrical forum online. General electrical questions and answers can be found in the electrical forum.
Top