Translations:Residual current device/12/en

A small amount of current - .1-.2 A - can be sufficient for an electric shock to be lethal, yet the overcurrent protection devices installed in electrical systems for lighting and outlets are generally 15 A or more. Additionally, overcurrent protection devices typically have a time delay to avoid accidentally opening (disconnecting) the circuit if there is a brief surge of current required by a surge load. If there is insufficient current flowing to activate the overcurrent protection device, this can lead to a many faults and potential hazards going unnoticed until there is an accident. An RCD is far more sensitive - can be activated by as little as 5-30 mA (.005-.03 A) of current - and will activate within 25-40 ms (.025-.04 seconds). It is recommended that an RCD is chosen with a 30 mA (.03 A) trip value.