What this SIRIUS breaker does in a motor branch
The magnetic short-circuit trip responds at 400 A, so it clears a bolted fault fast enough to protect the contactor downstream without welding the main contacts. The S0 frame size keeps the width at 45 mm — three of these fit in a standard 145 mm wide DIN-rail section, which matters for panel density. Depth is 96 mm, so it clears a 100 mm deep enclosure but check gland-plate clearance if the backplane is tight.
Clearance and mounting — what fits where
The 3RV6321-4EC10 needs 50 mm clearance above and below for air circulation and arc-chamber venting, 30 mm at the sides. Zero clearance forwards and backwards — it can sit flush against a backplate or enclosure door. That 50 mm vertical gap is non-negotiable if you want the breaker to trip free under fault without ionized gas tracking to adjacent metalwork. Terminal capacity: screw-type terminals accept 2 x (1 to 2.5 mm²) solid/stranded or 2 x (2.5 to 10 mm²), with a tightening torque of 2 to 2.5 N·m. For finely stranded wire with ferrule, it takes 2 x (1 to 2.5 mm²), 2 x (2.5 to 6 mm²), or a single 10 mm². That covers most panel-building wire sizes up to the 32 A rating without needing adapter lugs.
Lifecycle and compliance — what the nameplate tells procurement
Relative humidity 10 to 95 % non-condensing. Shock resistance 25 g / 11 ms per IEC 60068-2-27 — survives a forklift bump into the panel or a nearby press hit.