Discuss Cable to outbuilding in the Electrical Wiring, Theories and Regulations area at ElectriciansForums.net

J

johntom

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Hi
i've been to look at a job today that involves power and lighting to a brick outbuilding (my first outside job). The outbuilding is 1 meter from the main house. There is already a 2.5mm cable coming through the main house wall at a height of 7' which then goes into the outbuilding for the socket (accross the 1 meter span). Is this acceptable or do i need to replace with swa or should/can i use 2.5mm in conduit etc?
 
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You can use 2.5mm T&E as long as the cable has some form of mechanical protectiion. i.e conduit etc
 
M

Mac

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  • #3
Agree with notabrightspark.Add a fused spur for the lighting and remember to change the fuse to a 3 amp
 
J

johntom

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  • #4
Hi
Why a fused spur for the lights ? could you explain ?
also is plastic conduit acceptable?
 
J

johntom

  • Thread Starter Thread Starter
  • #7
Hi
are you saying that you can use 2.5mm from the CU to the outbuilding then (via a 3amp fused spur) power the lighting circuit in addition to the radial ( all from the 16amp in the cu) or am i miss reading this?
I had proposed to run a 1.5 and a 2.5 from separate mcb's for the 2 circuits.
thanks for you help
 
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You could run the T&E into a small CU in the garage via a fused spur, and run your lighting and sockets from the CU.
 
F

fanta

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  • #9
Are we forgetting earth leakage protection here ????????????????????????????
 
K

KFORDHUNTER

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  • #10
I would suggest running the 2.5mm from the house to the outbuilding in a conduit, or change it for swa to offer mechanical protection, protect using an rcd from the property. Install seperate c/u in outbuilding comprising of 16a radial and 6a lighting, only need mcbs in outbuilding.

Or you can give them my number and i will have a look at it for them, having to explain a job like this on here fills me with dread every time, are you a member of any organinsations niceic etc
 
J

johntom

  • Thread Starter Thread Starter
  • #11
Hi
yes i'm a member of an organisation and yes i fully understand the procedure you have highlighted. I was just interested in the post about using the fuse spur with lights and power as it seemed to suggest running them both from 1 supply. Forums like this are a helpful learning tool for many people - i am sure you had to learn !
 
A

alland1979

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  • #13
If you are getting paid to do a job do it right, 4mm Swa to a 2 way splitter then run your lights from a 5a mcb and your socket from a 20 and protect them with a 32 amp mcb from the house.
 
M

Mac

  • Thread Starter Thread Starter
  • #14
If you are getting paid to do a job do it right, 4mm Swa to a 2 way splitter then run your lights from a 5a mcb and your socket from a 20 and protect them with a 32 amp mcb from the house.
He maybe on a budget and i don't see why as the 2.5 T&E is already there in the outbuilding he can't utilise that.;)
 
S

spark1

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  • #16
If there are any mettalic pipes or other extraneous conductive parts [metal structures in contact with the ground],then the minimum size cable will have to be 10mm2 ,unless you TT the installation in the outbuilding.



spark1
 
M

Mac

  • Thread Starter Thread Starter
  • #17
If there are any mettalic pipes or other extraneous conductive parts [metal structures in contact with the ground],then the minimum size cable will have to be 10mm2 ,unless you TT the installation in the outbuilding.



spark1
Why would you do that.The Op stated that the building is only a metre away from the house.Personally it doesn't need spiked and i would use the existing cable for the power and lighting by adding a spur for the lights:cool:
 
A

alland1979

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  • #18
Granted there is a 2.5mm there at the moment, but is it protected? open to the elements? if its a job and he wants to get repeat business he should do it in Swa. I accept it might be more costly but wait till the homeowner gives him hassle when the cable fails due to being exposed to the elements
 
M

Mac

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  • #19
Granted there is a 2.5mm there at the moment, but is it protected? open to the elements? if its a job and he wants to get repeat business he should do it in Swa. I accept it might be more costly but wait till the homeowner gives him hassle when the cable fails due to being exposed to the elements
If it's only feeding 1 socket,i'd pull the cable back to the point of exit from the house and put it in pvc conduit.:D
 
S

spark1

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  • #20
Macca . the outbuilding is remote from the existing main building.....be it 1m. or 100m. therfore if it is to utilize the existing fault protection of EEBAD [ADS],then the equipotential zone extends to the outbuilding which means 10mm2 bonds to any extraneous conductive parts whithin it. Alternatively the outbuilding can form its own equipotential zone by creating aTT system.............if no extraneous conductive parts then no problem !


spark1
 
M

Mac

  • Thread Starter Thread Starter
  • #21
Macca . the outbuilding is remote from the existing main building.....be it 1m. or 100m. therfore if it is to utilize the existing fault protection of EEBAD [ADS],then the equipotential zone extends to the outbuilding which means 10mm2 bonds to any extraneous conductive parts whithin it. Alternatively the outbuilding can form its own equipotential zone by creating aTT system.............if no extraneous conductive parts then no problem !


spark1
So what you're saying is,if you had a shed in your back garden with an existing supply already feeding a socket,you would still spike the shed.:confused:
 
S

spark1

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  • #22
If there where extraneous conductive parts insidethe shed and the supply cable was less than 10mm ,on a tncs supply,then i would probably run in a 10mm2 seperate bonding conductor from the M.E.T in the house....if this was not easily done then yes i would TT the shed........if no extraneous conductive parts then the problem does not exist.....The o.p doesnt say either way on this issue
 
M

Mac

  • Thread Starter Thread Starter
  • #23
If there where extraneous conductive parts insidethe shed and the supply cable was less than 10mm ,on a tncs supply,then i would probably run in a 10mm2 seperate bonding conductor from the M.E.T in the house....if this was not easily done then yes i would TT the shed........if no extraneous conductive parts then the problem does not exist.....The o.p doesnt say either way on this issue
Ok mate i give up.You win.Goodnight.Just about to watch Rollerball on Ch5
 
S

spark1

  • Thread Starter Thread Starter
  • #24
It wasnt a competition Macca..just trying to help the o.p.

..your team qualified for next seasons Champions league eh ! Congrats....Liverpool fan myself....will see you there

Goodnight !



spark1
 
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