Twin and Earth riser - buried in the wall.

[South Spark]

Putting a new CU into a flat. The riser is protected by a fused switch (immediately after the meter). The riser is in 16mm T+E i.e non armoured. I can't see it anywhere so it must be within the fabric of the building Is this a non compliance?

 

[telectrix]

only if it's < 5omm from the surface of a wall, and/or the cpc is inadequate for earthing or bonding requirements.

 

[Wilko]

As Tel says - it's normally a 6mm cpc on 16mm T&E and may not be sufficient for an earthing conductor.

 

[Ian1981]

If the cable is < 50 mm from surface then it requires additional protection in the form of
A 30mA rcd
B cable has sufficient mechanical protection covering it (3mm plate steel)
C cable is installed in earthed metal containment (conduit or trunking)
D cable has an earthed metal covering such as swa which can withstand fault currents from being Penitrated by nails and screws.

If cable is buried in a wall with metal parts other than screws then depth is irrelevant and cable must be protected by options A-D

As the cable is exiting to cu and it would cause major disruption to do either of the options then I would personally just make a remark on the test certificate

As has already been covered by the other lads posts bonding is something that needs considering as already said the cpc in 16mm will be 6mm.
Only really acceptable if it's a TN-S system or TT.

 

[LankyWill]

As Tel says - it's normally a 6mm cpc on 16mm T&E and may not be sufficient for an earthing conductor.

Hope it's not PME in that case

 

[Ian1981]

As Tel says - it's normally a 6mm cpc on 16mm T&E and may not be sufficient for an earthing conductor.

A 6mm may be satisfactory as a cpc provided the Adiabatic equation is satisfied, however if you mean as a combined cpc/ bonding conductor then if pme it won't be.

 

[Rpa07]

Consider that can of worms truly OPEN!

 

[Wilko]

A 6mm may be satisfactory as a cpc provided the Adiabatic equation is satisfied, however if you mean as a combined cpc/ bonding conductor then if pme it won't be.

Yes, that's it exactly

 

[Risteard]

In the south of Ireland 16mm^2 T&E has a 10mm^2 cpc, although as stated BS cable has a 6mm^2 cpc.

 

[South Spark]

It's TNS - Adiabatic says it'll do. See what I can do to persuade the punter to go for an SWA replacement/ surface mounted.