SENTRON 5SQ2170-0KA05 — 1-pole C-curve MCB, 5 A, 3 kA
The Siemens SENTRON 5SQ2170-0KA05 is a 1-pole miniature circuit breaker (MCB) with a C-curve tripping characteristic, rated 5 A at 240 V AC, 50 Hz. Breaking capacity is 3 kA per EN 60898 — the standard for household and similar installations, certifying overcurrent and short-circuit protection in final circuits. Overvoltage category 3 and energy limiting class 3 mean it handles distribution-level transients and limits let-through energy for downstream equipment. IP20 finger-safe terminals suit enclosed panel mounting; the 55 mm depth and single width unit (approx. 18 mm) fit standard DIN-rail enclosures without crowding neighboring devices.
At 5 A, it protects a 1.1 kW resistive load at 240 V or a smaller motor branch. The 3 kA breaking capacity is adequate for most final sub-distribution boards within a building, but if your fault level at the panel exceeds 3 kA (common near a transformer or in industrial switchgear), you'll need a higher-rated upstream device or a different breaker. The single pole switches line only; neutral is not switched, which is standard for single-phase final circuits in TN systems.