Amazingly the E5 group seam to want to go away from PME.
I'm not sure about "amazingly". As far as I can see, TN-C-S is, in the majority of senses, a cheaper (for DNOs) but
inferior alternative to TN-S, particularly when it results from 'conversion' from a failed TN-S sheath.
As I see it, near all the 'features' of TN-S are 'downsides', primarily relating to the oft-discussed (albeit rare) potentially serious consequences which can arise if the CNE conductor of a TN-C-S supply develops a fault.
If there is any 'upside', I suppose it is probably 'more reliable' in some senses (hence cheaper to maintain) - in that, although potentially serious when it does happen, loss of a TN-C-S CNE is probably much rarer than malfunction/loss of a TN-S sheath.
It wouldn't be quite so bad if the 'M' of 'PME' meant "many" as well as "multiple" (which I used to think it
did mean!), but I gather that (particularly in 'conversions' from TN-S) it often only has one earth (at the end of the cable run) in addition to the primary earth at the transformer.
I may be wrong, but I think there are some countries in which TN-C-S is outlawed?
Kind Regards, John