SENTRON 5SY6440-7CC — 4-Pole C-Curve MCB at 40 A
The Siemens SENTRON 5SY6440-7CC is a 4-pole miniature circuit breaker with a C-tripping characteristic, rated 40 A at 35 °C and providing a 6 kA breaking capacity certified to EN 60898. This is the part for a 3-phase plus neutral branch circuit where the load is moderate-inrush — motors, transformers, or groups of LED drivers — and the fault current at the panel does not exceed 6 kA.
The 40 A rating is valid at 35 °C ambient. At 40 °C the continuous current drops to 38.12 A; at 45 °C to 37.12 A; at 50 °C to 36.12 A; and at 55 °C to 35.08 A. The operating range spans -40 °C to 75 °C, with humidity limits of 95% up to 55 °C, 55% up to 70 °C, and 35% at 75 °C.
The combined terminal at both top and bottom accepts the same conductor range, so wiring order is reversible.
Compliance and Material Declarations
Halogen-free and silicon-free construction is declared, which matters for outgassing-sensitive environments such as clean rooms, medical equipment, or aerospace panels where silicone contamination can inhibit relay contacts. The MCB is sealable — a lead seal can be fitted through the housing to prevent tampering in metered or safety-critical circuits. Energy limitation class 3 is assigned per EN 60898, meaning the let-through energy under fault is low enough to protect downstream wiring without cascading damage.