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:
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.
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.
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.
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 requirement in the distribution board. Through this replacement, the protection level in electrical circuits is enhanced by additional personal safety.
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.
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.
Installation of RCBO is easier than RCCB. RCBO is designed to optimize the operation, facilitate troubleshooting and reduce inefficiencies and downtime.
RCBO’s 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)
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.
The sensitivity range of RCBO is limited compared to RCCB. RCCB is available up to 1000mA but RCBO is available up to 300mA.
The lifespan of RCCB is longer than RCBO. Because RCCB trips only when there is a residual current on the circuit.
If you want to learn more about residual current devices, you can check and buy "Residual Current Devices: Selection, Operation, and Testing"