10 A C-Curve 2-Pole MCB — Panel Fit and Trip Coordination
The Siemens 5SJ4210-7HG42 is a SENTRON miniature circuit breaker rated 10 A at both AC and 30/40 °C, with a C tripping characteristic — magnetic trip between 5 and 10× rated current, so it handles moderate inrush from motor starters and contactor coils without nuisance trips on a 24 VDC control loop. Two-pole design (2P) with both poles switched; neutral conductor is not switched.
Thermal Derating and Ambient Envelope
Rated 10 A continuous at 30 °C and 40 °C; derates to 9.7 A at 45 °C, 9.4 A at 50 °C, 9.1 A at 55 °C. At 60 °C the rating drops sharply to 0.88 A — this is the thermal-magnetic element's ceiling, not a typo.
Integration — DIN Rail and Vibration
Vibration resistance tested to 50 m/s² at 25–150 Hz and 60 m/s² at 35 Hz (4 s) — holds up on machine-mounted panels near rotating equipment. IP20 with connected conductors, IP40 in the handle range — suitable for enclosed panels where incidental finger contact is the only exposure. Sealable design allows lockout/tagout. Halogen-free and silicon-free construction for sensitive environments like clean rooms or food processing.