The Siemens 5SJ4114-8HG42 is a SENTRON miniature circuit breaker (MCB) in the 5SJ4 design, a single-pole unit with a D tripping characteristic rated at 0.3 A at AC or DC (60 V max DC). At 0.3 A it suits very small loads: control transformers, solenoid valve banks, or indicator lamp circuits. Rated current holds at 0.3 A up to 40 °C ambient; above that it derates smoothly to 0.25 A at 60 °C — a detail worth noting if the breaker lives near a heat source in a sealed panel.
Mounting and environment
Depth is 70 mm, installation depth the same — no extra clearance behind the rail. Mounts in any position. IP20 with conductors connected; IP40 in the handle area.
Construction and compliance notes
Halogen-free and silicon-free construction — important for environments where outgassing could contaminate optics or sensitive contacts. Sealable, so a lockout/tagout hasp can be fitted per LOTO procedure. Terminals are combined (top and bottom) with a tightening torque of 3.5 Nm for copper conductors at 60/75 °C. Vibration resistance rated at 50 m/s² over 25–150 Hz and 60 m/s² at 35 Hz — solid for machinery-mounted panels.