Discuss swa buried in render? in the Electrical Forum area at ElectriciansForums.net

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ExArmy

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got an extension to price for, was planning on putting a sub main in from the existing board(3036, 100mA RCD upfront, TT) out and along the exterior wall, then back in to a new board which will supply the new rings, lights etc in the the extension.
customer asked if the cable could be buried in the new render/dash? i said i wouldn't advise it, but i'm not sure on the exact regs. they seemed pretty keen to get it hidden, despite the fact that the original supply cable was clipped direct anyway. is there anything to say i can't bury this in the wall?
 

telectrix

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not till someone comes along to fit a trellis or some such garbage that the lady of the house wants, and drills into your SWA.
 
E

Edward Amsden

how far is the supply away from the income
what is the income.
are you splitting the tails?
SWA?
 
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ExArmy

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how far is the supply away from the income
what is the income.
are you splitting the tails?
SWA?
from the existing DB to the extension DB, about 10 metres max. incomer is 16mm tails which come down and into the house, the tails are jointed to some SWA running along the fascia about 200m to a pole transformer.
was planning on doing the sub main in SWA, would be a kitchen ring, another ring, 2 lighting circuits and a 3kw cooker on the new board
 
1

1shortcircuit

It's mechanically protected so you could run it buried in the wall following a zig zag pattern. Not your fault if someone then drills through it:thumbsup

You could try burying it over 50mm for extra precaution but it might take a while and create a weakness in the structure;)

Give them a price for burying it and then see them change their tune :thumbsup
 

keniff

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Well you can bury it in the ground.......but it has to be 500 deep.
I'm with you on the advice.
Hello mate is there actually a reg for this or is it guidance, I was looking for this the other day on buried cables
 
1

1shortcircuit

Thought it was 600mm myself. Still what's a hundred Mill between friends? lol
 

keniff

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I thought it varied between situations, like in flower bed then deep, under a patio doesnt have to go quite so deep etc just to keep cable out of harms way on every different scenario
 

ipf

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Hello mate is there actually a reg for this or is it guidance, I was looking for this the other day on buried cables
A bit 'tongue in cheek' regarding the rendering depth. 522.8.something or other mentions sufficient depth and mechanical protection but no specific depth. Depends on various situations and degrees of safety, so it's up to the installer and how he reads it. Building regs may come into it in some situations.
 
1

1shortcircuit

A bit 'tongue in cheek' regarding the rendering depth. 522.8.something or other mentions sufficient depth and mechanical protection but no specific depth. Depends on various situations and degrees of safety, so it's up to the installer and how he reads it. Building regs may come into it in some situations.
Agreed, Building regs cover depth of chases and this would be my angle of defence if a client of mine wanted a cable buried in the wall rather than clipped direct to an external wall.
 
D

Deleted member 26818

There's no minimum or maximum depth for burying a cable in the ground except whee the installation is Agricultural.
As for concealling cables in walls, the cables must be provided with additional protection.
One acceptable method of additional protection, is to use an SWA cable
 

Guitarist

Regular EF Member
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Norfolk
Agree with spin. No actual reg, but guidelines which you have to justify. Generally 500mm under a lawn, 600mm where digging may occur, any depth you deem safe when going under pathways. I always put my swa in ducting for additional protection when underground. Just remember that render can affect PVC.
 
E

Engineer54

got an extension to price for, was planning on putting a sub main in from the existing board(3036, 100mA RCD upfront, TT) out and along the exterior wall, then back in to a new board which will supply the new rings, lights etc in the the extension.
customer asked if the cable could be buried in the new render/dash? i said i wouldn't advise it, but i'm not sure on the exact regs. they seemed pretty keen to get it hidden, despite the fact that the original supply cable was clipped direct anyway. is there anything to say i can't bury this in the wall?
Why would you want a sub main cable and a separate CU at all, for just an extension to a house?? This seems like lunacy to me, ...you have an old 3036 CU protected by 100mA RCD on a TT system, that you plan to leave in place and then planning to install a new small 30mA CU. ...Do you consider this existing set up satisfactory for a TT system installation??

So why not advise your client to upgrade his existing CU to a new unit, that can cover ALL the circuits in this house, as well as providing a decent 30mA level of primary protection for all the circuits in the installation. Even better, is to also change out the standard 100mA up front RCD with an S type unit which will provide additional protection in the event of one of the 30mA RCD's failing in the new CU....
 
S

Swicade

It's unlikely the render will be deep enough to cover the clipped SWA....which will mean channeling out the wall a considerable depth thus weakening the structure of the wall itself.

Also it's possible that after a short while of the render being done it wont be long before a long hairline crack will appear in the render directly along the route of the SWA....spoiling the look of the new render (painted render will show up even more).


These are the excuse's/reasons i'd be quoteing to the customer tbh. Putting the SWA inside some conduit/pipe the same colour as any existing rainwater/soilstack/guttering can often be a better idea.
 

Guitarist

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It's unlikely the render will be deep enough to cover the clipped SWA....which will mean channeling out the wall a considerable depth thus weakening the structure of the wall itself.

Also it's possible that after a short while of the render being done it wont be long before a long hairline crack will appear in the render directly along the route of the SWA....spoiling the look of the new render (painted render will show up even more).


These are the excuse's/reasons i'd be quoteing to the customer tbh. Putting the SWA inside some conduit/pipe the same colour as any existing rainwater/soilstack/guttering can often be a better idea.
I often run swa in conduit outside, because as you say, it blends in with surrounding plastic. That said, if they are rendering and painting, then the cable can be painted at the same time and will be hard to notice.
 

Strima

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St Neots
It's unlikely the render will be deep enough to cover the clipped SWA....which will mean channeling out the wall a considerable depth thus weakening the structure of the wall itself.
Render tends to be roughly 10mm so not much change of hiding it as Swicade has pointed out.

Why not run circuits as E54 has said? Seems logical to me.
 
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ExArmy

Electrician's Arms
Messages
715
Location
cumbria
Why would you want a sub main cable and a separate CU at all, for just an extension to a house?? This seems like lunacy to me, ...you have an old 3036 CU protected by 100mA RCD on a TT system, that you plan to leave in place and then planning to install a new small 30mA CU. ...Do you consider this existing set up satisfactory for a TT system installation??

So why not advise your client to upgrade his existing CU to a new unit, that can cover ALL the circuits in this house, as well as providing a decent 30mA level of primary protection for all the circuits in the installation. Even better, is to also change out the standard 100mA up front RCD with an S type unit which will provide additional protection in the event of one of the 30mA RCD's failing in the new CU....
reason for the sub main and seperate board is it keeps it simple. the board is quite far from the extension, would mean going through 2 rooms with no access from above (laminate flooring and finished wood floor) so i would have to pull down the lat n plaster ceiling. and, i would have to upgrade the board to connect up the new circuits, and if i were to find any faults then fixing them would be time consuming and costly.
if money and time was no object then obviously the whole house would need rewired, but it's not.
 
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