ETI KZS-4M differential automatic circuit breaker 3P+N 16A C type AC 6kA (2174024)

The ETI KZS-4M differential automatic circuit breaker is intended for protection of electrical circuits against overload, short-circuit, and residual current. It combines the functions of an automatic circuit breaker and a residual current device in one housing, which makes it suitable for installation in distribution boards of residential buildings, commercial premises, and small administrative facilities. Such a device is used where both overcurrent protection and protection against leakage currents are required on the same line. This model has a 3P+N pole configuration, so it is designed for three-phase circuits with a neutral conductor. The rated current is 16 A, which makes the device appropriate for grouped circuits with moderate load. The C tripping characteristic allows operation in circuits with short-term inrush currents, for example where equipment with motors or other loads with a higher start-up current is connected. The rated residual current is 0.03 A, which provides protection against electric shock by disconnecting the circuit when leakage current is detected. The AC type indicates that the device responds to sinusoidal alternating residual current. The breaking capacity of 6 kA allows safe disconnection under significant short-circuit currents typical of standard low-voltage networks. The rated frequency of 50/60 Hz supports use in electrical systems operating at either of these frequencies. Compliance with IEC/EN 61009 confirms that the device meets the requirements for differential automatic circuit breakers. For wiring, the device supports conductor cross-sections from 1 mm² to 25 mm², which gives flexibility during installation in distribution boards with different cable sizes. In practical use, the KZS-4M can be applied for lighting circuits, socket circuits, and power lines where combined protection against overload, short-circuit, and residual current is needed. The ETI design is aimed at standardized modular installation and integration into switchboard assemblies where compact protective equipment with clearly defined electrical ratings is required.