I think this topic deserves it's own thread.
pensdown said:Unless your concealed cables have been installed in accordance with one of the five options (very unlikely) you will need to install 30mA earth leakage protection to every circuit that has concealed cables. So a 100mA type S as a mains switch is unsuitable. Also, it will not meet 314.1
If the CU is Class II,(531.4.1) the sub-circuits are protected by DP RCBO's and the bus bars are insulated - YesNotHimAgain said:Are you suggesting that a front end device is not required.
That should be a short meeting - safe isolation? Shock protection has nothing to do with 100mA type S RCCD'sThe review is taking place because of some problems that have been identified concerning shock protection between the outgoing terminals of a main switch and the supply side terminals of an RCD downstream of a non-RCD main switch.
I'm not sure what 531.4.1 has to do with this because I never mentioned a single RCCD.This is an old chestnut that is similar to the reason for the requirements in 531.4.1.
314 is very relevant. It's the minimum requirement for circuit design and it applies to every installation.314 is, as ever, not really relevant and generally unworkable - it is far more important that you achieve shock protection.
I'm missing how a 100mA RCCD provides shock protection?I would advise anyone that is considering omitting a front end device on a TT system to confirm with the manufacturer in writing that satisfactory shock protection will be achieved.
531.4.1 - Class II CU's solve that problem.Note that if a fault occurs between the outgoing circuit from a non-RCD main switch that is 'behind' any RCD the extraneous-conductive-parts and the exposed-conductive-parts in the installation may attain full supply potential and may not be disconnected.