Have got this question in the combustion chamber but i am finding different answers on the net and with the regs.I need to fit an electric shower for a family member the house is council owned so every thing has to bang on,I would like to chase MCW pipe in to the wall but not 100% certain if this is allowed under the water regs I did the WRAS course 6 years ago and I always said some of the wording in some of the regs where confusing and could be misinterperated depending on your take of the english language.I have down loaded relevant section from DEFRA Section 2 paragraph 7 states "no fitting shall be embedded in any wall or solid floor"Then G7.3 goes on to say pipes can be installed in a pipe sleeve or duct.Then at the end there are drawings of pipes bedded in a chase wrapped in impermeable tape.If any one can clarify this i would be very grateful.