Modular Residual Current Devices for Industrial Protection

Bender has introduced three modular residual current devices (MRCDs) designed for industrial environments with high load currents and complex electrical conditions. Developed in accordance with DIN EN 60947-2 Annex M, the devices provide protection in applications where conventional residual current devices (RCDs) may not operate reliably.

Combined measurement, monitoring and protection
The MRCD portfolio includes devices for both all-current-sensitive and AC/DC-specific applications. The LINETRAXX SmartDetect MRCDB425 variants detect residual currents across a frequency range up to 20 kHz (type B/B+), enabling monitoring of modern power electronics and variable-frequency systems. The MRCD410R extends coverage to alternating and pulsed currents within 42–72 Hz (type A).

All devices integrate measurement, alarm, and protection functions in a single unit. They trigger a connected circuit breaker without delay at a residual current threshold of 30 mA. For higher thresholds, configurable up to 3 A, a time delay can be applied to avoid unnecessary tripping during transient conditions.

In addition, configurable early warning thresholds allow the system to generate alarms before reaching shutdown levels. This enables predictive intervention and supports continuity of operation in critical processes.

Suitability for high-load industrial environments
The devices are designed for use in electrical systems with high voltages and load currents, where conventional RCDs may be prone to nuisance tripping or may not support the required current types. Compliance with IEC 60364 supports their use for personal protection, fire prevention, and system protection.

Typical application areas include welding equipment, crane systems, industrial lifting systems, medical imaging equipment such as computer tomographs, and DC charging infrastructure. These environments often involve non-linear loads and frequency converters, requiring all-current-sensitive detection capabilities.

Integration into industrial monitoring systems
The MRCD devices support integration into existing electrical and automation systems through a Modbus RTU interface. This enables centralized monitoring and parameterization within industrial control environments.

Configuration can also be performed via an NFC interface using a mobile application, allowing parameter adjustments even when the device is not powered. This supports flexible commissioning and maintenance workflows.

Device variants and operational interfaces
Two variants of the MRCDB425 are available with different user interfaces. One version provides status indication through multi-color LEDs, while the other includes a high-resolution color TFT display for detailed diagnostics and parameter visualization.

Both variants feature a wide-range power supply supporting AC/DC 100–240 V and DC 24 V, enabling deployment across diverse industrial power systems.

Role in modern electrical safety architectures
As industrial systems increasingly incorporate power electronics, variable-speed drives, and DC components, conventional protection devices may not provide adequate coverage. MRCDs address this gap by enabling accurate residual current detection across a broader frequency spectrum.

By combining monitoring, early warning, and protection functions with system integration capabilities, these devices support more reliable and adaptable electrical safety strategies in industrial environments.

Edited by Romila DSilva, Induportals Editor, with AI assistance.