Residual Current Relay 1P+N 16A 30mA ETI KZS-1M-UNI

ETI KZS-1M-UNI is a residual current (earth leakage) relay for 1P+N circuits with a rated current of 16 A and a residual operating current of 30 mA. The device monitors the difference between live and neutral conductors and operates an external circuit breaker or load when a leakage current above the set threshold is detected. Intended for installation in distribution boards, it provides additional protection against electric shock and reduces fire risk by allowing automatic disconnection when insulation faults or stray currents occur.

Advantages

The relay offers compact design and simple integration into standard DIN-rail distribution panels, enabling leakage monitoring without replacing existing breakers. With a 30 mA sensitivity it meets common safety requirements for personnel protection in living spaces and light commercial applications. The product is passive in terms of switching action, relying on a connected breaker or contactor to isolate the circuit, which allows flexible configuration with a variety of upstream protective devices.

Suitable for

• Residential distribution boards where additional leakage detection is needed
• Small commercial or office installations requiring earth-leakage monitoring
• Retrofit projects where fitting a separate residual current device is impractical
• Circuits feeding appliances with potential insulation degradation risks

When it may not be suitable

This residual current relay does not provide direct overcurrent protection and must be used together with an appropriate circuit breaker sized for 16 A or other upstream protective devices. It is intended for 1P+N single-phase systems and is not suitable for three-phase installations without a compatible relay design. For locations requiring automatic disconnection at different sensitivity levels or integrated fault current interruption, a combined residual current device (RCD/RCD breaker) may be more appropriate.

Key specifications

• Configuration: 1P + N (single-phase with neutral)
• Rated operational current: 16 A
• Residual operating current (sensitivity): 30 mA
• Function: detection of imbalance between live and neutral conductors (earth leakage)
• Mounting: DIN-rail compatible housing for distribution boards
• Intended use: detection and signaling to trip an external breaker or load

How to use

Install the relay in the distribution board on a standard DIN rail and wire the live and neutral conductors through the device according to the wiring diagram. The relay senses differential current and closes its control contact when leakage exceeds 30 mA; this contact should be wired to the trip coil of a circuit breaker or to a contactor that interrupts the supply. Verify correct installation and operation by performing recommended insulation and functional tests after wiring, and periodically check the relay and associated protective device for reliable operation.

What to consider before purchase

• Confirm the installation is single-phase 1P+N and compatible with a 16 A rated device
• Ensure presence of an appropriate upstream circuit breaker or trip device to be operated by the relay
• Check available DIN-rail space and panel wiring layout for easy integration
• Verify local regulations and required sensitivity for residual current protection (30 mA is typical for personal protection)

Usage recommendations

Use the relay together with a correctly rated circuit breaker or contactor and follow installation standards. Test operation after commissioning and during periodic maintenance to ensure the residual current relay and the associated protective device trip reliably when leakage occurs.