Side-by-side mounting is allowed — no gap needed between units. That 73 mm depth means it clears a standard 80 mm deep enclosure backplate with room for wiring.
Rated insulation voltage 690 V, with AC-3 and AC-3e maximum rated voltage also 690 V — so it's good for 400 V line-to-line motor circuits in most of the world. The AC-3 rating (motor starting, not full-load) governs the real use: at 400 V and 60 °C it's rated for 13 kW motor load; at 690 V and 60 °C, 22 kW. Those are the numbers a panel builder sizes against. Switching frequency maxes out at 750 1/h for AC-3 duty, 1 000 1/h for AC-1 (resistive), and 10 000 1/h for DC switching. Mechanical life typical is 30 million operations — that's a bin that won't cycle out for years in normal service.
RoHS substance prohibition date 05/01/2012 — compliant with the EU RoHS directive as of that date.