Trip Class 10 is the deciding factor for motor protection coordination. It matches the thermal characteristic of most standard squirrel-cage induction motors during start-up, allowing them to accelerate without nuisance tripping while still protecting against overload. If your motor has a longer acceleration time (high-inertia loads like centrifuges), you'd need a Class 20 or 30 relay — but for the majority of conveyor, pump, and fan applications, Class 10 is the right call. The Size S2 form factor is the mechanical interface. It mounts directly onto the corresponding S2 contactor (e.g., the 3RT1036 series), so the assembly clips together without additional hardware. Auxiliary contact ratings are given for several control voltages: 1 A at 24 V, 3 A at 120 V, 2 A at 230 V, and 1 A at 400 V. The 3 A at 120 V rating is the one most often used in North American control panels; the 1 A at 24 V covers the DC control common in European designs. Power dissipation is 4.6 W per pole. In a multi-motor panel with several relays, that heat adds up — account for it in your enclosure thermal calculation to avoid derating adjacent components.
Main circuit terminals accept stranded wire from 0.75 to 35 mm² (or 2x 0.75 to 25 mm²), and AWG from 18 to 1. Auxiliary circuit terminals take solid wire 2x 0.5 to 1.5 mm² or 2x 0.75 to 2.5 mm², and AWG 2x 20 to 16 or 2x 18 to 14. That covers the range from control wiring up to the motor feeder — no adapter lugs needed for standard installations. Clearance distances are specified: 0 mm upwards, forwards, backwards, and downwards, with 6 mm at the side. This means the relay can be stacked directly against adjacent devices vertically and horizontally as long as the side gap is maintained — typical for DIN-rail or mounting-plate layouts where space is at a premium.
The 100% relative humidity rating during operation means it's suitable for unconditioned indoor environments — no condensation, but high ambient moisture is acceptable. Shock resistance is 8g for 10 ms, which covers most industrial vibration from contactors and motors in the same panel. The substance prohibition date of 07/01/2006 aligns with RoHS compliance for the European market.