An interface is disclosed for a self powered protection relay that uses mechanical switches for its configuration. The protection relay can include a base relay for measurement of line current and for generation of a trip signal, and a Human Machine Interface (HMI) unit for specifying, by a user, a base setting of an operating parameter of the protection relay. The base relay can be self-powered from the line and the HMI unit can include an auxiliary power supply. The protection relay is configured with mechanical switches provided in the protection relay. The HMI unit in the protection relay is designed to detect and alert the user of the relay of any change in the base setting carried out with one or more mechanical switches provided in the relay in powered and unpowered conditions of the base relay.