In an overload relay, a tripping actuator 12 has a first magnet 18 and a moveable contact carrier 20 has a second magnet 28 mounted opposed to the first magnet. A moveable contact 22 on the moveable contact carrier is urged by repulsion between the magnets, to make a normally closed connection with a stationary contact 24, when the tripping actuator is in an ON position 15 and the contact carrier in a first stable position 26′. The magnets pass through an over-center tripping position (T) when the tripping actuator is moved to an OFF position 23 in response to an overcurrent condition sensed by a bimetallic thermal overload sensor 16. The magnets repel each other after passing through the over-center tripping position, to thereby urge the moveable contact into a second stable position 26, away from the stationary contact, to break the normally closed connection with the stationary contact.