Combined residual current operated devices (RCBO)

Our customers often confuse residual current protection and combined residual current protection, and some do not see the difference between these devices at all. The difference between residual current protection and combined residual current protection is that the former does not have overcurrent protection, which must be installed additionally, for example in the form of a circuit breaker. Combined residual current protection devices are devices that combine the functions of a circuit breaker and residual current protection in one device.

What is differential current and where does it come from?

The differential current is the difference between the current flowing through the phase conductor to the consumer and the current returning through the neutral conductor. The main element of any residual current protection is the differential transformer, which constantly monitors this difference.

During normal operation of the electrical installation, the incoming and outgoing currents are equal. When a ground fault occurs, part of the current does not return through the neutral conductor. When the difference reaches the set value, the residual current protection switches off the electrical circuit and prevents dangerous situations.

Types of residual current protection

• Type AC – designed for protection against alternating current and standard household applications.
• Type A – detects both alternating and pulsating direct current. Suitable for modern electrical appliances and electronic devices.
• Type B – mainly used in industrial applications and systems with frequency converters, charging stations and photovoltaic installations.

How to choose a suitable residual current device?

1. Sensitivity – 10mA for high-risk areas, 30mA for personal protection, 100mA and 300mA for fire protection and general protection of installations.
2. Rated current – must be consistent with the load of the protected electrical circuit.
3. Type AC, A or B – the choice depends on the type of connected consumers and the presence of electronic devices.
4. RCCB or RCBO – RCCB provides protection against leakage currents, while RCBO combines leakage, overload and short circuit protection.

Advantages of RCCB residual current devices

• Protecting people from electric shock.
• Reducing the risk of fire caused by electrical leakage.
• Quick shutdown in emergency situations.
• Increasing the safety of electrical installations.
• Compliance with modern electrical safety requirements.

Conclusion

RCCBs are a mandatory element of any modern electrical installation. They provide reliable protection against leakage currents and contribute to the safety of people, equipment and buildings. In the E.NEXT catalog you will find solutions for domestic, commercial and industrial applications with different rated currents, sensitivities and types of protection.