Interrupting capacity and tripping curve for motor-starting loads
The 5SJ4218-8HG41 is a 2-pole miniature circuit breaker from the Siemens SENTRON 5SJ4 series, specified with a D tripping characteristic. That curve allows a higher inrush multiple — typically 10–14× rated current — before the magnetic trip fires, which makes it the right choice for motor-starting, transformer, or other inductive loads where the start-up surge would nuisance-trip a B or C curve breaker. Rated interrupting capacity is 10 kA per EN 60898 and 15 kA per IEC 60947-2 at 400 V AC. The 15 kA figure under the industrial standard means this breaker can clear a fault up to that level without welding contacts or cascading failure upstream — important when coordinating with a larger main breaker in a panel.
DIN-rail fit and environmental limits
Snaps onto standard 35 mm DIN rail, occupying 2 modular width units (36 mm wide). The 70 mm depth leaves clearance for wiring in shallow enclosures. Mounting position is unrestricted. Ambient temperature range spans -40 °C to 75 °C, with a pollution degree 3 rating and overvoltage category III. The housing is halogen-free and silicon-free, and the breaker is sealable — a lead seal can be fitted through the handle to prevent tampering after commissioning.