What this MCB is and where it fits
The Siemens 5SY5406-7CC is a 4-pole SENTRON miniature circuit breaker with a C-curve tripping characteristic, rated 6 A at 35 °C and carrying a 10 kA DC breaking capacity per IEC 60947-2. It snaps onto a DIN rail via the quick assembly system and occupies 4 modular width units (72 mm) in the panel. The IP20 enclosure (with connected conductors) suits it for installation inside a distribution board or control cabinet — not for wet or outdoor locations.
Ratings that decide the fit
The C-curve means the magnetic trip activates at 5 to 10 times rated current — standard for motor and transformer branch circuits where inrush is moderate. At 35 °C the breaker holds 6 A continuous; derate to 5.32 A at 40 °C, 4.95 A at 45 °C, 4.55 A at 50 °C, and 4.1 A at 55 °C (–). If the panel ambient runs above 40 °C, size the upstream load to the derated figure, not the 35 °C number. The DC breaking capacity of 10 kA at up to 1000 V DC is the headline number for DC bus or battery-string protection. That 10 kA is the maximum fault current the breaker can safely interrupt under IEC 60947-2 — if the available fault current at the panel exceeds that, you need a current-limiting upstream device or a higher-rated breaker. Operating temperature spans -40 °C to 75 °C, with humidity derating: max 95% RH up to 55 °C, dropping to 55% at 70 °C and 35% at 75 °C. Vibration resistance per IEC 60068-2-6 is ±1 mm at 5–25 Hz and 50 m/s² at 25–150 Hz — fine for machine-mounted panels but not for direct engine-mount without isolation.
Panel integration notes
Mounts in any position on a DIN rail via the quick assembly system. Depth is 76 mm, with 70 mm installation depth behind the panel face. Width of 72 mm equals 4 modular units.