What this MCB is and where it fits
The Siemens 5SY7414-8 is a 4-pole miniature circuit breaker from the SENTRON family, designed for branch-circuit protection in industrial control panels and distribution boards. Its D tripping characteristic (10–20× In) makes it the right choice for loads with high inrush currents — motor starters, transformers, or welding equipment — where a B or C curve would nuisance-trip on startup. Rated 0.29 A at 400 V AC (50/60 Hz), it carries a breaking capacity of 15 kA per EN 60898 and 50 kA per IEC 60947-2, giving you headroom for high-fault installations.
Ratings that matter for fit
The 0.29 A rating at 40 °C is the continuous current the breaker can carry without tripping; at higher ambient temperatures the value derates stepwise to 0.25 A at 60 °C (–). That derating curve is critical when the breaker sits in a crowded enclosure — if your panel ambient runs above 40 °C, you need to account for the reduced ampacity. The 50 kA SCCR under IEC 60947-2 means it can safely interrupt a fault up to that level without upstream coordination failure, which is the figure most industrial specs call for; the 15 kA EN 60898 rating covers residential and light commercial installations where the standard is different.
Panel integration notes
The 5SY7414-8 occupies 4 modular width units (72 mm wide) on a DIN rail, with a depth of 76 mm and an installation depth of 70 mm. It mounts in any position and accepts conductors via combined top and bottom terminals. Rated IP20 with connected conductors — suitable for enclosed distribution boards, not for wet or washdown environments. The sealable design allows lockout/tagout without removing the breaker.