Siemens Betagard 5SL4106-0RC — 6 A, Z-characteristic MCB
The Siemens Betagard 5SL4106-0RC is a 1-pole miniature circuit breaker rated 6 A at AC with a Z tripping characteristic, designed for sensitive circuit protection where low overcurrent thresholds are critical. It breaks 10 kA per EN 60898 and 15 kA per IEC 60947-2, giving you headroom for high-fault installations. The Z curve trips between 2 and 3 times rated current — tighter than a B curve — so it catches semiconductor or control-transformer overloads before they cook the winding, but won't nuisance-trip on normal inrush from a 24 VDC supply. Rated voltage hits 440 V AC in single- or multi-phase operation, and DC rating maxes at 72 V — enough for most control-circuit rails. The 1-module-width (18 mm) body snaps onto standard DIN rail, and with pollution degree 3 and overvoltage category III it's rated for industrial panels, not just residential load centers.
Z-curve application and thermal derating
The Z characteristic (2–3× In trip band) is the main reason you'd pick this over a B or C curve: it protects circuits where even a brief 4× overload would damage downstream electronics — PLC power supplies, fieldbus couplers, instrumentation loops. At 30 °C ambient the breaker carries 6.5 A; at 50 °C it's back to 6 A; at 60 °C it's 5.7 A. That derating matters if the breaker lives in a crowded enclosure next to transformers or drives. Mounting position is unrestricted, so you can lay it sideways in a shallow gland box if needed.
Panel integration and compliance
Snap-on DIN-rail mount, 18 mm wide (1 MW). Depth is 76 mm, installation depth 70 mm — verify clearance against the enclosure door or busbar shroud. IP20 with connected conductors, so it's panel-internal only; no washdown rating. Sealable (padlockable toggle) for lockout/tagout. Halogen-free and silicon-free construction, which matters for clean-room or high-reliability environments where outgassing contaminates contacts or optics. Vibration resistance tested to 50 m/s² at 25–150 Hz per IEC 60068-2-6 — holds up on a machine frame or conveyor line.