What it is and what it does
The Siemens 5SY6101-8 is a 1-pole SENTRON miniature circuit breaker from the 5SY6 series, rated 1 A at 400 V AC with a D tripping characteristic. That D-curve means it tolerates high inrush currents — typically 10 to 20 times rated current for short durations — making it the right choice for motor starter circuits, small transformers, or solenoid valve banks where the start-up surge would nuisance-trip a B- or C-curve breaker. The 30 kA breaking capacity per IEC 60947-2 gives headroom for high-fault installations; the 6 kA rating per EN 60898 covers the standard household/commercial panel application.
Environmental and compliance notes
Halogen-free and silicon-free construction — relevant for clean-room or semiconductor-adjacent installations where outgassing matters. Rated for ambient temperatures from -40 °C to 75 °C, with humidity derating above 55 °C (95% RH up to 55 °C, tapering to 35% at 75 °C). Pollution degree 3, overvoltage category III, so it's suited for industrial environments with conductive dust or occasional condensation. Sealable with a lockable cover for lockout/tagout procedures.