The S2 frame size (114 mm high, 55 mm wide, 130 mm deep) is a common footprint across the SIRIUS line, so panel layouts transfer between frame-matched contactors and overload relays.
That 6 mm side gap is the tightest constraint; adjacent devices need that clearance for arc flash and heat dissipation.
AC-3 switching frequency is 700 operations per hour (also rated 700 1/h for AC-3e). That's the sustained mechanical rate for motor starting — not a burst rating. AC-4 (plugging/inching) drops to 200 1/h because the contactor sees full locked-rotor current on every make and break. The main contact spring life is 10 million operations typical, which is the mechanical endurance before the contactor needs replacement.