The Complete Guide to Residual Current Operated Circuit Breaker (RCBO)

24th May 2023

Residual Current Operated Circuit Breakers (RCBOs) are vital components in electrical systems, providing combined protection against overcurrents and residual currents. This comprehensive guide aims to provide a detailed understanding of RCBOs, including their definitions, types, functions, applications, and a special focus on the renowned manufacturer TOSUNlux.

Definition of Residual Current Operated Circuit Breaker 

A Residual Current Operated Circuit Breaker (RCBO) is an electrical widget that integrates the features of a residual current device (RCD) and a miniature circuit breaker (MCB) into a single unit. It provides protection against both overcurrents and residual currents, making it a versatile solution for electrical safety.

Types of Residual Current Operated Circuit Breaker 

  • Type AC RCBO

Type AC RCBOs are designed to protect against AC residual currents. They are commonly used in residential and commercial applications where the main source of electrical current is alternating current (AC).

  • Type A RCBO

Type A RCBOs provide protection against both AC and pulsating DC residual currents. They are suitable for environments with potential DC residual currents, such as locations with electronic equipment or renewable energy installations.

  • Type B RCBO

Type B RCBOs offer comprehensive protection by detecting and responding to all types of residual currents, including AC, pulsating DC, and smooth DC currents. They are typically used in industrial and specialized applications with varying types of electrical loads, such as medical facilities and data centers.

Functions of Residual Current Operated Circuit Breaker 

  • Overcurrent Protection

RCBOs function as miniature circuit breakers (MCBs), providing protection against overcurrents caused by short circuits or excessive electrical loads. They detect and interrupt the circuit when the current exceeds the rated limit, preventing damage to the electrical system and connected devices.

  • Residual Current Protection

RCBOs incorporate the functionality of a residual current device (RCD) to detect imbalances in current caused by leakage to the ground. When a residual current is detected, the RCBO rapidly trips, disconnecting the circuit to prevent electric shocks and mitigate the risk of electrical fires.

Applications of Residual Current Operated Circuit Breaker 

  • Residential Buildings

RCBOs are mostly installed in homes to provide enhanced electrical safety for lighting circuits, power outlets, kitchen appliances, and other residential electrical circuits. They offer protection against electrical faults and minimize the risk of electric shocks for household occupants.

  • Commercial and Industrial Facilities

RCBOs are widely used in commercial establishments, including offices, retail stores, factories, and warehouses. They ensure the safety of employees, customers, and valuable equipment by detecting and mitigating electrical faults.

  • Healthcare Facilities

RCBOs are essential in hospitals, clinics, and healthcare facilities to protect critical medical equipment, patient care areas, and electrical systems. They contribute to maintaining a safe environment for patients and medical staff by preventing electrical hazards.

  • Data Centers

RCBOs are extensively used in data centers to protect servers, networking equipment, and sensitive electronic devices. They ensure reliable power distribution and prevent downtime caused by electrical faults.


RCBOs are essential components in electrical systems, providing combined protection against overcurrents and residual currents. When it comes to the best quality RCBOs, TOSUNlux stands as a trusted manufacturer that offers advanced solutions. Choose TOSUNlux for superior protection and durability in your electrical installations.

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