The thermal-magnetic trip gives you both overload protection (thermal) and short-circuit protection (magnetic). The magnetic trip is set at 341 A, which is about 19 times the rated current — that's a fast trip for a hard fault, but it won't nuisance-trip on motor inrush. It's rated for AC-3 duty (squirrel-cage motor starting) and AC-3e (the enhanced version for high-efficiency motors) per IEC 60947-4-1, so it's the right class for switching motor loads directly. The 18 A rating covers a 7.5 kW motor at 400 V, 9 kW at 500 V, or 15 kW at 690 V.
Breaking capacity — what it means on your line
The breaking capacity is 100 kA Icu at 230/240 V AC, 15 kA at 400/415 V, and 6 kA at 690 V. At 400 V, the 15 kA Icu still covers most industrial panel bus faults.
Built-in auxiliary contacts and phase failure protection
It also has phase failure sensitivity per IEC 60947-4-1 — if one phase drops out, the breaker trips, protecting the motor from single-phasing. That's a useful feature if you're trying to avoid a separate disconnect switch in the panel.
Dimensions are 89 mm high, 54 mm wide, 78.5 mm deep. Mounting position is horizontal or vertical — no restriction there. The power terminals are screw clamp, accepting 1 to 6 mm² solid or 1.5 to 6 mm² flexible without ferrules, or 1 to 4 mm² with ferrules. Tighten to 1.7 N·m. IK04 impact rating means it can take a light knock during installation. Power dissipation is 2.5 W per pole, so 7.5 W total at full load — factor that into your panel thermal budget.
Certified to EN/IEC 60947-2 (breakers), EN/IEC 60947-4-1 (contactors and motor-starters), UL 60947-4-1, and CSA C22.2 No 60947-4-1. Also complies with IEC/EN 60335 for appliance applications. Fire resistance tested to 960 °C per IEC 60695-2-11. Climatic withstand per IACS for marine environments.
Durability and mechanicals
Rated for 100,000 electrical cycles at AC-3/AC-3e at 415 V at rated current, and 100,000 mechanical cycles. That's a solid 100k-cycle life — not a throwaway part. Shock rated to 30 Gn for 11 ms, vibration to 5 Gn from 5 to 150 Hz, so it holds up on a machine that shakes.