Conduit or not?

[scottmeister71]

I hear conflicting reports about whether you should bury cable in the wall using conduit or just use cable clips and plaster straight over it.
Can somebody please advise because it would be easier to just use cable clips.

 

[andy]

I hear conflicting reports about whether you should bury cable in the wall using conduit or just use cable clips and plaster straight over it.
Can somebody please advise because it would be easier to just use cable clips.

just use capping. if its in a permitted area, then no protection is needed. i.e plaster over. if its somewhere else then it is to be in conduit

 

[scottmeister71]

Is a kitchen a permitted area?

 

[topsparks]

The permitted area andrew is refering to are the 'zones' that cables should be run in:
if the cables run vertically or horizontally from the switch or socket, then they can just be plastered over.
If they run diagonally they must be protected with conduit unless buried at a depth of greater than 50mm

The kitchen is a 'special location' under part P of the building regs so is notifiable.

Nick
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[Spark123]

If there is a risk of the plasterer hitting the cable with a trowel it should be capped.

 

[BenStiller]

1: DO YOU INTEND LIVING THEIR?
2: DO YOU INTEND USING COMMON SENSE?
3: DO YOU WANT A REPLY OFF BAN ALL SHEDS?

 

[ban-all-sheds]

What am I, the bogeyman??

I always advise the use of PVC conduit, as it makes future modifications so much easier - cables just buried in plaster, or even under capping, can't be pulled out. You do have to watch the derating though.

Sometimes metal conduit is required:

http://www.niceic.org.uk/downloads/C5-43.pdf

http://www.niceic.org.uk/downloads/concealedcables.pdf

 

[mapj1]

plastic capping and plastic capping offer no magical protection against screws, drills or nails. The main purpose is to make the plastering easier, and less likely to have to be redone because of cable damage.
However, conduit has the advantage of being re-threadable, and so is my preferred, being more future proof -assumed cable life 20 years (and the rest).
Both conduit and capping require cables to be derated (i.e. a heavier cable used or less current) if 2 or more cables share the enclosure, as the cooling is not as good as direct burial.
In any case, if running outside of a line of least surprise (i.e. not vertical or horizontal from a visible fitting, and cable ducting not visible from the surface) then either earthed metal conduit, or a similar level of protection, (SWA is common in conservatories, where routing is a real pig) or at least 2" deep from the surface.

 

[ChrisR]

But from the first of Ban-a-s references,

Regulation 522-06-06 (as revised by
Amendment No 2 to BS 7671: 2001) requires that
where a cable is concealed in a wall or partition at a depth of less than 50 mm from any surface of the wall or partition, the cable must:
(i) incorporate an earthed metallic covering which complies with the requirements of the
Regulations for a protective conductor of the circuit concerned,

As I read it that precludes cables OR plastic conduits near the surface. Wosgarnon?

 

[mapj1]

That is indeed quite true, for a cable not in a line of least surprise. You need to read the text around that clause to realise that they expect the risk to cables in line with a fitting to be reduced. Quite why I'm not sure, as in practice J public seems quite happy to drill above lightswitches and alongside sockets, as well as on of diagonal positions.
Fortunately, even so, such accidents are rare.

 

[ChrisR]

Thanks for your patience - I'd read it as i) AND ii) AND iii) where it says OR !

 

[Steve]

Saw a blatant disregard/ignorance for cable routes once. 240v Socket mounted in a classroom, on a steel pillar, cable run in plastic self adhesive conduit up to ceiling. Teacher had gone around putting staples thru the conduit, to mount kid's work up. Whether the classroom is still there, i dont know. I just hope that steel pillar is earthed.

 

[Big_Spark]

Saw a blatant disregard/ignorance for cable routes once. 240v Socket mounted in a classroom, on a steel pillar, cable run in plastic self adhesive conduit up to ceiling. Teacher had gone around putting staples thru the conduit, to mount kid's work up. Whether the classroom is still there, i dont know. I just hope that steel pillar is earthed.

I think you mean mean Mini Trunking Crafty, they don't make self-adhesive conduit thankfully.

 

[plugwash]

it sounds to me like someone fixing to the only thing they could get thier staples into which happened to be cable trunking.

bad design imo

 

[ban-all-sheds]

Saw a blatant disregard/ignorance for cable routes once. 240v Socket mounted in a classroom, on a steel pillar, cable run in plastic self adhesive conduit up to ceiling.

So the cable was in an acceptable route - it was not concealed.

The fault was the teacher's, not the installer....