On 30/05/2019 08:19, PeterC wrote:
On Wed, 29 May 2019 21:27:25 +0100, ARW wrote:

On 29/05/2019 11:41, Tricky Dicky wrote:
The wall where the garage supply cable will be buried in the wall is an exterior cavity wall with the internal wall being cinder type breeze blocks so quite easy to chase out to a depth of 50mm. Elsewhere the cable will run either through trunking or on the surface. I am a little concerned about carving halfway through the blocks for a 2m vertical run and I am not sure if they are already the hollow type, the ones I have had to sink boxes into elsewhere appear solid but you never know?

It's 50mm from final finished surface not 50 mm into the blocks.

Just to clarify: if the cable(s) are protected by a 30mA, 30ms RCD or RCBO
do they have to be a) protected b)as far in a 50mm?
It seems that surface-mounted mini-trunking would be OK; what if that were
flush with or just below the surface?


If the cables are less than 50mm from the final finished surface then
30mA RCD protection is required. They need no further protection other
than to be run in the required zones.

ie

http://wiki.diyfaq.org.uk/index.php/...lectric_cables

The 18th edition now requires RCD protection of domestic lighting no
matter what cable or installation methods you use.

--
Adam