out to BS 7671:2008, in a domestic or similar premises with a TT earthing system, you[...] would be based on the protective device in place, i.e. the MCB. Appendix 3 of BS 7671:2008 gives
(17th Edition)? Answer: BS 7671: 2008 (the 17th Edition) requires additional 30mA RCD protection[...] at the main position to protect all circuits in this situation meets the intention of BS 7671: 2008