Details: Newsletter 1: RCCB

“Residual current circuit breaker”

(Download:Boletin 001 EN SFG 2017 05 03)

Known for acronym in English (RCCB), also known as residual current device (RCD, “residual current device”), is a component that instantly cuts an electrical circuit to prevent serious damage from an electrical shock in process. Damage can continue to occur even after receiving an impact, for example by a fall.


This electrical installation device is designed to quickly and automatically disconnect the circuit when an unbalanced current is detected.

Under normal circumstances, both conductors, line and neutral, are expected to conduct equal currents and any difference indicates a short circuit or other electrical abnormality, such as a leak, is present. A leak indicates that there is a risk of electrocution which can damage a person.

A current leak can result in electrocution damage or death, especially if current leakage passes through the human torso. A current of approximately 30mA is potentially sufficient to cause cardiac arrest or serious injury if it persists for more than a fraction of a second. RCCBs are designed to disconnect wires quickly to prevent severe damage from such events, typically described as that the RCCB is powered.