err.. Mr earth everything my way and ignore everyone else....so you get a shock because you havent earthed properly in the first place.we really need to get reading up on the purposes of proper earthing on this forum.
were not talking about earthing. if you didnt have the polarity wrong, then turning off with SP MCB would isolate and leave installation dead. leaving with wrong polarity means when you isolate via SP MCB, installation is still live. i dont really care if you want to add an RCD or not, the fact still remins that it has been left in a dangerous state, and the earthing has nothing to do with this.