A method of controlling a mechanical contactor including at least one pair of contacts for conducting a mains current (Im) when the contactor is in a closed position, and an electromagnet arranged to close the contactor, and maintain the contactor in the closed position, by forcing the pair of contacts towards each other when a control current (Ic) runs through a coil of the electromagnet. The method includes, while the contactor is in the closed position, obtaining an indication of unintentional separation of the contacts, and in response to the obtained indication, opening the contactor and maintaining the contactor in an open position by turning off the control current.