If you have read it where is the bit that excludes swa being used as tails? This is what @Risteard said. No - it's a requirement of BS7671 that the Earthing conductor enter the ferrous enclosure within the same entry as the live tails. You liked the post so I presume you agree with the statement, Clearly it's wrong and I have given examples to show otherwise. You already said yourself there is no definition of tails so tails could equally include SWA. This has everything to do with the op, your the one trying to de-rail it. The advice given is not correct. Do you not think the op or anyone else reading this is not entitled to know the correct answer rather than your own opinion? Actually, to be fair, your not short on those are you. And for the record, your the one making the argument. I am correct and YOU are wrong. Why on earth do you think I'm going to roll over and say, hey that's cool?