You may think they have thought about this, but there are a great many smaller UPS and gensets that are indeed floating output, and this is IT, not TN-S whatever they say, only a solid metal link from N-E makes it TN-S. The assumption often that the loads will either be double insulated, or one item or logical item (a free standing desk of equipment perhaps) that is class 1.
The capacitors are often set more by considerations of meeting EMC specifications, rather than thoughts of how downstream ADS may work - in small systems it often does not need to, as the inverter just dies under overload.

Note that the UK is quite unusual in prohibiting in law an NE connection in a consumer installation connected to the public network. There are some cases when it would be easier if it was worded in a way that allowed it under limited specific conditions (like if the earth cross-section was the same as the neutral). I have had a few conversations over the years with folk from places where it is allowed who are surprised at the extra complexity it can introduce.
(consider this NZ/AUS example of how to wire an extension - where would we put an RCD ? )

Mike

mapj1 said:

Note that the UK is quite unusual in prohibiting in law an NE connection in a consumer installation connected to the public network. There are some cases when it would be easier if it was worded in a way that allowed it under limited specific conditions (like if the earth cross-section was the same as the neutral). I have had a few conversations over the years with folk from places where it is allowed who are surprised at the extra complexity it can introduce.
(consider this NZ/AUS example of how to wire an extension - where would we put an RCD ? )

The situation that can arise with multiple N-E connections, if the installation is not properly arranged, is the unwanted operation of RCDs in single-phase systems where the neutral is one of the poles of supply. Not an issue with "split-phase" or "centre-tapped transformer" single-phase systems though ... but in those arrangements the UPS would again be floating.

mapj1 said:

Note that the UK is quite unusual in prohibiting in law an NE connection in a consumer installation connected to the public network. There are some cases when it would be easier if it was worded in a way that allowed it under limited specific conditions (like if the earth cross-section was the same as the neutral). I have had a few conversations over the years with folk from places where it is allowed who are surprised at the extra complexity it can introduce.
(consider this NZ/AUS example of how to wire an extension - where would we put an RCD ? )

The situation that can arise with multiple N-E connections, if the installation is not properly arranged, is the unwanted operation of RCDs in single-phase systems where the neutral is one of the poles of supply. Not an issue with "split-phase" or "centre-tapped transformer" single-phase systems though ... but in those arrangements the UPS would again be floating.