The Siemens 5SY6414-7CC is a 4-pole miniature circuit breaker from the SENTRON series, rated at 0.3 A with a C tripping characteristic and a 6 kA breaking capacity per EN 60898. It protects downstream wiring and loads against overcurrent and short-circuit faults in 400 V three-phase panels — common in mechanical engineering and industrial control cabinets. The C-curve (5–10× In) is the standard choice for moderate inrush loads like contactor coils, small transformers, and control-circuit supplies.
Ratings and thermal derating
Rated 0.3 A at 35 °C ambient, the breaker derates to 0.28 A at 40 °C, 0.26 A at 45 °C, 0.25 A at 50 °C, and 0.23 A at 55 °C. If your panel runs hot — say 50 °C inside a sealed enclosure — the 0.25 A limit means a 0.3 A load will nuisance-trip. Size the load to the derated figure, not the nameplate. The 6 kA breaking capacity at 440 V AC meets EN 60898 for domestic and industrial installations. Overvoltage category III and pollution degree 3 suit fixed-installation distribution boards where transients and conductive dust are expected.
Mounting and panel fit
Occupies 4 modular width units (72 mm wide) on a DIN rail. Depth is 76 mm, installation depth 70 mm — leaves clearance behind the gland plate for wiring. Snap-on quick assembly system; mounting position any orientation. IP20 with connected conductors, so it belongs inside a closed panel, not exposed to washdown.