RCCB vs RCBO: A Comprehensive Comparison Guide

When designing an electrical installation each circuit has to be protected against overcurrent at its origin. The overcurrent protection device shall ensure the simultaneous breaking of both phase and neutral conductors. Some appliances should be supplied by a dedicated circuit having the appropriate cross-sectional area, overcurrent, and residual current protection. Different protection devices are being used for overcurrent and residual current protection. The usage of RCCB and RCBO is really popular in electrical installation. But do you know the differences between these two devices? I compared them for you.

Differences Between RCCB and RCBO

RCCB and RCBO are different protection devices. We listed the main differences below:

1. Definition

Definitions of RCCB and RCBO are different.

RCCB stands for residual current circuit breaker.

RCBO stands for residual current circuit breaker with integral overcurrent protection.

The residual current circuit breakers with overcurrent protection are a technologically advanced and comprehensive solution.

2. Overload protection

RCCB protects against the only residual current. The main duty of RCCB is to protect human life. It does not have overload protection.

RCBO protects against residual current and overload. RCBO protects humans and equipment. Both devices have an isolation function.

3. Short circuit protection          

RCCB protects against the only residual current. It does not have short-circuit protection.

RCBO protects against short circuits.

Both devices have an isolation function.

4. Dimensions and space-saving

RCBO combines residual current, overload, and short circuit protection in a single device. It allows considerable time savings in wiring operations. It also reduces the space needed in the switchboards.

Generally, RCCB is wider than RCBO. RCCB must be used in series with an MCB or fuse which protects them from the potentially damaging thermal and dynamic stresses of any overcurrent. If you mount RCCB and MCB in series, you will need more space inside the electrical cabinet.

Moreover, in old buildings, it is very easy to replace the existing 1-pole MCBs with an RCBO without additional space requirements in the distribution board. Through this replacement, the protection level in electrical circuits is enhanced by additional personal safety.

5. Price

RCCB is cheaper than RCBO. An RCBO is almost 2 or 3 times more expensive than an RCCB. That’s why the market size of RCCB is much bigger than RCBO.

6. Applications

RCCB has wider application areas. It can be used in any industrial, commercial or residential application.

In any application where the dimensions represent a potential barrier, residual current circuit breakers with overcurrent protection guarantee reliable and complete protection against overcurrent and earth fault currents. RCBOs are suitable where space is a precious resource, such as zones for marinas and camping, switchboards for temporary environments such as yards or exhibitions, industrial sockets, and power generators.

7. Easy wiring

Installation of RCBO is easier than RCCB. RCBO is designed to optimize the operation, facilitate troubleshooting and reduce inefficiencies and downtime. RCBOs combine the functions of an RCCB and an overcurrent protection device (OCPD) in one unit, which eliminates the need for separate devices and wiring. This can make the installation process quicker and more efficient. Additionally, RCBOs often have built-in diagnostic features that can assist with troubleshooting and reduce downtime.

8. Breaking capacity

RCBOs have a high breaking capacity. RCBO combines protection against earth-fault current and overcurrent in a single device, guaranteeing high breaking capacities. (Generally, up to 10kA)

9. Indicator

Some RCBOs are equipped with an earth fault indicator to detect any earth fault trip. (For example, the blue window below) Earth fault indicator indicates any earth fault trip. This feature reduces downtime for maintenance and prevents any misinterpretations of the device and system status.

10. Limited sensitivity

The sensitivity range of RCBO is limited compared to RCCB. RCCB is available up to 1000mA but RCBO is available up to 300mA.

11. Lifespan

The lifespan of an RCCB may be longer than an RCBO because an RCCB trip only when there is a residual current on the circuit, whereas an RCBO also trips when there is an overcurrent or short circuit on the circuit. However, it is important to note that the lifespan of an RCCB or RCBO will also depend on factors such as the quality of the device, the environment in which it is used, and the frequency of use.