MK Sentry Residential RCD provides an indication of an earth fault and contact status. It offer a comprehensive selection of devices designed to meet most residential, commercial and light industrial requirements. The range is two pole, AC fault current sensitive with a selection of current ratings from 16 to 80A and is available in a variety of tripping sensitivities. When in the OFF position a contact gap of 4mm is present, enabling Sentry RCDs to be used as isolating switches where appropriate. The operating dolly may be locked in either the ON or OFF position without affecting the ability of the trip mechanism to operate, that is the RCD is trip-free. It is not possible to hold the contacts closed when a fault condition exists. The RCD incorporates a filtering device to provide protection against transient surges in the supply to the unit, thus reducing the occurrence of unwanted tripping. It is designed to fully comply with the requirements of BS EN 61 008:1995, IEC 1008:1990 standards.