SIEMENS IEC

A-Curve and D-Curve refer to the trip characteristics of Siemens 5SY4 supplementary protectors. A-Curve devices trip at higher fault currents than B-Curve but lower than C-Curve, making them suitable for circuits with moderate inrush currents. D-Curve devices have a higher trip threshold, designed for circuits with high inrush currents, such as those with transformers or motors. The choice depends on the specific load characteristics and coordination with upstream protection. Both curves are available in the 5SY4 series across various current ratings and pole configurations.

Yes, the Siemens 5SY4 series supplementary protectors are UL1077 listed. UL1077 is the standard for supplementary protectors, which are intended to provide overcurrent protection in addition to branch-circuit protection. They are not a substitute for branch-circuit breakers. The UL1077 listing ensures the devices meet specific safety requirements for supplementary protection in industrial control panels and similar applications. This listing is clearly marked on the product and in the technical documentation.

Siemens IEC supplementary protectors in the 5SY4 series have a breaking capacity of 10 kA at 400 V AC. This rating indicates the maximum short-circuit current the device can safely interrupt without damage. It is important to verify that the breaking capacity meets or exceeds the available fault current at the installation point. For DC applications, the breaking capacity may differ; consult the datasheet for specific ratings at 72 V DC. The 10 kA rating at 400 V AC is consistent across many models in the series.

Yes, Siemens 5SY4 supplementary protectors are rated for DC applications up to 72 V DC. The DC rating is typically lower than the AC rating, and the breaking capacity may also differ. For example, a device rated 10 kA at 400 V AC may have a different DC breaking capacity. It is essential to check the specific product datasheet for DC ratings and ensure proper polarity and connection. These protectors are suitable for DC control circuits, such as those found in industrial automation and renewable energy systems.

Siemens IEC supplementary protectors in the 5SY4 series use screw clamp terminals. These terminals accept solid or stranded wires and provide a secure connection. The screw clamp design allows for easy installation and maintenance without special tools. Terminal capacity varies by model; typical wire ranges are 1-25 mm² for solid and stranded conductors. Always follow the manufacturer's torque specifications to ensure reliable electrical contact and to prevent damage to the terminals or wiring.

Yes — 3G Electric (S) Pte. Ltd. supplies SIEMENS IEC products. We stock the SIEMENS IEC catalog and supply genuine factory-original products with full manufacturer warranty and technical support.