Sav,
I my memory serves me well, the “equipotential terminal” was a feature of DIN (German) standards relating to “rooms intended for clinical use”. They were useful in, for instance, ECG recording areas (stress testing set-ups would be an example) by providing a “central earthing point” for all significant equipment in the room.
Connections to equipment would be made using temporary earthing cables, with clips or press-stud ends. Electrically, then all equipment casings would be bonded together at the equipotential terminal (using daisy-chain, or star, or whatever gave best results). Technically, this point would be different from protective earth (although you would expect the two to be at the same potential – ie, “earth”). Using this set up could sometimes eliminate electrical interference, although I expect the original idea was to do with electrical (patient) safety as we now know it. Remember that back in the “good old days”, electromedical equipment in some parts of the world sometimes worked better with an earthing wire running to a clip on the plumbing!
Note that a similar “stud” is found on the back panel of quite a few bits of electromedical kit intended for the IEC or “international” markets.
I am surprised that equipotential terminals have been installed in a new refurbishment (maybe there’s a new requirement that I don’t know about – quite likely). I expect the clue is in the fact that you mention that the outlets have metal cases. If I were you I would simply regard it as a “belt and braces” feature that may be handy when carrying out electrical safety tests of the outlets concerned and of any equipment nearby. Bottom line is, no need to worry.
