The Siemens 5SY7604-8 is a 4-pole (3P+N) SENTRON miniature circuit breaker with a D tripping characteristic, rated 4 A at 35 °C on a 400 V AC 50/60 Hz system. The 4-pole 3P+N configuration switches three phases and the neutral, common for three-phase distribution boards feeding mixed single- and three-phase loads.
Temperature derating and ambient limits
The 4 A rating holds at 35 °C ambient. Above that, derate linearly: 3.81 A at 40 °C, 3.71 A at 45 °C, 3.61 A at 50 °C, 3.5 A at 55 °C, and 3.39 A at 60 °C. If the panel internal temperature runs near 50 °C — common in a sealed enclosure with drives — the effective continuous current drops to 3.61 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 % up to 75 °C.
Physical integration and compliance
Dimensions: 72 mm wide (4 modular units), 90 mm high, 76 mm deep, with an installation depth of 70 mm. Sealable, halogen-free, and silicon-free construction. Compliance documentation includes the manufacturer's declaration per the SENTRON series — RoHS, REACH, and the relevant IEC/EN standards are covered in the standard product documentation.