RCDs

The function of residual current circuit breakers (RCCBs) is to provide protection against direct contact by diverting currents to ground. They are essential for personal safety.

Where is the residual current circuit breaker installed?

The RCCB is installed by connecting it in series between the MCB (Main Circuit Breaker) and the first miniature circuit breaker (MCB) of the first power circuit, inside the protection and control panel of the house or business.

Types of Residual Current Circuit Breakers

• Class AC: This is the most commonly used and basic type, it protects against 50 Hz sinusoidal currents. It is used in homes and small offices.
• Class A (Super-immune): Protects against both sinusoidal and pulsating currents, mainly used in industrial environments.
• Class F: Protects against alternating, pulsating, and mixed currents (AC + DC). It is mainly used in industrial applications (frequency converters). It is the least commonly used type of RCCB.
• Class B: Protects against alternating, direct, and pulsating currents. It is an improved version of Class F. It is mainly used in the industrial sector and is currently the most widely used in this field.

RCCB Malfunction

Unexpected tripping of the RCCB can damage it and cause malfunction. This may expose people to great danger and serious consequences, as it would fail to detect leakage currents it was designed for. Another issue that may occur due to malfunction is that it becomes more sensitive, causing frequent unwanted tripping.

RCCB Maintenance

In industrial installations, periodic inspections required by the applicable regulations must be carried out.

In residential installations, there is no regulation requiring inspections, as these devices are quite reliable. However, they should be tested at least every 6 months to 1 year to ensure proper operation.

To test functionality, simply press the built-in test button. If it does not trip, it is not working correctly and should be replaced.

Special Residual Current Circuit Breakers

Self-resetting: When transient trips occur, these models are able to automatically reset, attempting several reclosures depending on the model. If after several attempts it keeps tripping, the device will stop trying and remain disabled.

Super-immune: They operate more selectively. In conventional RCCBs, nuisance tripping may occur when it should not. Super-immune types are more precise and reliable.