ABB IIRMR02 Residual Current Circuit Breaker – IIRMR Series

ABB IIRMR02 — Integrated Residual Current and Overcurrent Protection for Industrial Branch Circuits

The ABB IIRMR02 is a single-module Residual Current Circuit Breaker with Overcurrent protection (RCBO) belonging to ABB’s IIRMR series. It consolidates two discrete protection functions — residual current monitoring and thermal-magnetic overcurrent tripping — into a single 1P+N DIN rail device. This integration reduces panel footprint, eliminates the wiring interface between a standalone RCCB and MCB, and ensures that both protection mechanisms share a common tripping mechanism with coordinated response timing. In branch circuit design, the IIRMR02 occupies the final distribution tier, protecting individual circuits from both earth leakage faults and overload or short-circuit conditions without requiring auxiliary coordination relays.

The device is rated to IEC 61009-1 and EN 61009-1, the governing standards for RCBOs in low-voltage installations. Its residual current sensing element operates on the summation current transformer principle: the line and neutral conductors pass through a toroidal core, and any imbalance in the magnetic flux — caused by leakage current flowing through an unintended path to earth — induces a signal in the secondary winding. This signal is processed by the trip relay without dependence on the supply voltage, making the protection function line-voltage independent and therefore effective even during supply disturbances. The thermal-magnetic overcurrent element uses a bimetallic strip for inverse-time overload response and an electromagnetic solenoid for instantaneous short-circuit interruption, consistent with IEC 60898-1 tripping characteristic definitions.

Real-time Stock & RFQ: [email protected] | WhatsApp: +86 18359268345

Technical Parameters

Hardware Logical Analysis

The IIRMR02’s internal architecture reflects ABB’s approach to combining two functionally independent protection circuits within a mechanically unified housing. The residual current detection path and the overcurrent tripping path share a common trip bar but operate through separate actuator mechanisms, which is a deliberate design choice to prevent mutual interference between the two protection functions during fault events.

Summation CT and Signal Processing: The toroidal summation current transformer is wound on a high-permeability ferrite core. Under normal operating conditions, the vector sum of currents in the line and neutral conductors is zero, producing no net flux. A ground fault as low as 30 mA creates a measurable flux imbalance. The secondary signal is rectified and compared against a calibrated threshold by the trip relay coil. Because this circuit is self-powered from the fault current itself (not from the supply voltage), the IIRMR02 maintains protection integrity during brownout conditions — a critical requirement in industrial environments where supply quality is variable.

Thermal-Magnetic Overcurrent Element: The bimetallic strip is calibrated for inverse-time-delay response: at 1.13× In, the device does not trip within 1 hour (cold state); at 1.45× In, it trips within 1 hour. This characteristic prevents nuisance tripping on motor inrush or transformer magnetizing currents while still protecting cable insulation from sustained overload. The electromagnetic solenoid provides instantaneous response to short-circuit currents above the Type C threshold (5–10× In), with an arc interruption chamber designed to extinguish the arc within the rated breaking capacity of 6 kA.

EMC Design Considerations: The IIRMR02’s summation CT is shielded against external electromagnetic fields that could induce false trip signals. In industrial panels with variable-frequency drives (VFDs) or switching power supplies, high-frequency leakage currents can accumulate across multiple circuits. The Type A classification of the IIRMR02 means it responds to both sinusoidal (50/60 Hz) and pulsating DC residual currents, making it appropriate for circuits supplying single-phase rectifier loads such as SMPS-based control equipment. For circuits with significant high-frequency leakage (e.g., VFD motor cables), selective Type F or Type B RCBOs should be evaluated to avoid nuisance tripping.

Mechanical Endurance and Contact Architecture: The silver-alloy contact tips are rated for a defined number of mechanical and electrical operating cycles per IEC 61009-1 Annex H. The contact gap geometry is designed to withstand the rated impulse withstand voltage (Uimp), ensuring the device maintains dielectric integrity between line and neutral after repeated fault interruptions. The test button circuit allows periodic functional verification of the residual current trip mechanism without interrupting the overcurrent element, enabling maintenance teams to confirm protection integrity under live conditions.

System Integration Benefits

• Panel space reduction: Combining RCCB and MCB functions in a 2-module (36 mm) device frees DIN rail space compared to installing a separate 2-module RCCB plus a 1-module MCB, reducing enclosure size requirements in space-constrained installations.
• Wiring simplification: Eliminating the inter-device wiring between a standalone RCCB and MCB removes a potential source of installation error and reduces the number of termination points subject to thermal cycling and vibration loosening.
• Coordinated protection response: The shared trip bar ensures that both residual current and overcurrent faults result in simultaneous disconnection of line and switched neutral, preventing single-pole interruption scenarios that could leave neutral conductors energized.
• Voltage-independent residual current protection: The self-powered trip relay maintains earth leakage protection during supply undervoltage conditions, which is relevant in industrial sites with generator backup or unstable grid supply.
• Type A sensitivity for mixed loads: The 30 mA Type A rating provides personnel protection per IEC 61009-1 requirements while accommodating the pulsating DC leakage currents generated by single-phase rectifier circuits in control panels.
• Selective coordination with upstream devices: The 6 kA breaking capacity and Type C tripping characteristic allow coordination with upstream Type B MCBs or moulded case circuit breakers (MCCBs) in a cascaded protection scheme, ensuring that only the faulted branch is isolated without tripping the upstream feeder.
• Test button for in-service verification: Periodic actuation of the test button confirms the residual current trip mechanism is functional without requiring circuit de-energization, supporting preventive maintenance schedules in continuously operating facilities.
• IEC 60715 DIN rail compatibility: Standard 35 mm rail mounting ensures compatibility with ABB System pro M compact® enclosures and third-party DIN rail panels, simplifying retrofit and expansion projects.
• Accessory compatibility within IIRMR series: The IIRMR02 accepts ABB IIRMR series auxiliary contacts and alarm contacts, enabling remote fault signaling to SCADA or BMS systems without modifying the primary protection device.
• Compliance with IEC 61009-1: Full conformance to the international RCBO standard ensures acceptance in project specifications requiring certified protection devices, reducing procurement risk in regulated industries.

Quality Assurance & Global Logistics

Every ABB IIRMR02 unit supplied through siemensplc.com is sourced from verified ABB authorized distribution channels. Each unit is inspected upon receipt against the following criteria before being made available for sale:

• Visual inspection of housing, terminals, and labeling against ABB OEM specifications
• Authenticity verification via ABB product label and batch traceability documentation
• Packaging integrity check to confirm undamaged factory seals
• Certificate of conformity available upon request for project documentation

Our warehouse is located in Xiamen, China, a major logistics hub with direct access to international express carriers (DHL, FedEx, UPS) and sea freight consolidators. Standard in-stock orders are processed within 1–2 business days. Express air freight to Europe, Southeast Asia, the Middle East, and the Americas typically achieves delivery within 3–7 business days. Sea freight and consolidated shipment options are available for bulk orders. DDP (Delivered Duty Paid) terms are available for select destinations, simplifying customs clearance for buyers without established import infrastructure. All shipments include commercial invoice, packing list, and country of origin documentation. A 12-month warranty covers manufacturing defects from the date of shipment.

Contact Information

Email: [email protected]
WhatsApp: +86 18359268345
Web: siemensplc.com
Location: Xiamen, China
© 2026 siemensplc.com. All rights reserved.