On Site guide page 69 cable buried in plaster

My house has solid walls with plaster, I was going to groove the plaster and bury cable in it Do I need plastic conduit?
I've got the yellow on site guide, trying to work out what size cable to buy, re page 69 'installation reference methods'
Is that installation method A on page 69 'Enclosed in conduit in an insulated wall'
does that mean heat insulated or electrically insulated?
george
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It happens that DICEGEORGE formulated :

Heat insulation/ thermal insulation.
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On 05/10/2016 22:17, DICEGEORGE wrote:

No, you can bury a cable directly in plaster if you want.

Can't say without knowing what the circuit is going to be used for...
A normal 32A protected ring or 20A protected radial would typically use 2.5mm^2 T&E
Data here:
http://wiki.diyfaq.org.uk/index.php/Cables#T.26E_current_carrying_capacity

No.
If you bury the cable direct, then its method C, if install it in conduit and bury that, then its B.

Heat - since its the cable maximum temperature that dictates its maximum operating current. Hence the more thermal insulation the less current required to reach the maximum conductor temperature (typically 70 deg C for PVC insulated cables)
--
Cheers,

John.
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On 05/10/16 22:17, DICEGEORGE wrote:

No.
But I would (and did) use 20mm oval conduit - hardly needs any more depth and protects the cable from plastering trowel damage as well as allowing easy cable replacement.

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