A contactor (150; 250) comprising: a first power terminal (151a; 251a); a second power terminal (151b; 251b); a sub-circuit electrically connected between the first power terminal and the second power terminal, and comprising at least the following three elements connected in series: an electrical conductor portion (154; 254), a primary switch (153; 253) and a fuse (158; 258); the primary switch comprising a movable part driven by an actuator (156; 256); a magnetic sensor (155; 255) configured for measuring a primary current flowing through the electrical conductor portion (154; 254); a controller (160; 260) communicatively connected to said magnetic sensor (155; 255) for measuring said primary current flowing through the electrical conductor portion (154; 254), and operatively connected to said actuator (156; 256) for selectively opening and closing said switch (153; 253); wherein the contactor (150; 250) further comprises detection means (157; 257) for detecting whether the primary switch (153; 253) is actually open or closed; wherein the controller (160; 260) is configured for: i) measuring a primary current, and detecting if an overcurrent condition occurs; and if an overcurrent condition is detected, continuing with step ii); ii) operating the actuator (156; 256) to open the primary switch (153; 253); iii) detecting if the primary switch (153; 253) is effectively open; and if it is detected that the primary switch is still closed, blowing the fuse (158; 258). a first power terminal (151a; 251a); a second power terminal (151b; 251b); a sub-circuit electrically connected between the first power terminal and the second power terminal, and comprising at least the following three elements connected in series: an electrical conductor portion (154; 254), a primary switch (153; 253) and a fuse (158; 258); the primary switch comprising a movable part driven by an actuator (156; 256); a magnetic sensor (155; 255) configured for measuring a primary current flowing through the electrical conductor portion (154; 254); a controller (160; 260) communicatively connected to said magnetic sensor (155; 255) for measuring said primary current flowing through the electrical conductor portion (154; 254), and operatively connected to said actuator (156; 256) for selectively opening and closing said switch (153; 253); wherein the contactor (150; 250) further comprises detection means (157; 257) for detecting whether the primary switch (153; 253) is actually open or closed; wherein the controller (160; 260) is configured for: i) measuring a primary current, and detecting if an overcurrent condition occurs; and if an overcurrent condition is detected, continuing with step ii); ii) operating the actuator (156; 256) to open the primary switch (153; 253); iii) detecting if the primary switch (153; 253) is effectively open; and if it is detected that the primary switch is still closed, blowing the fuse (158; 258). i) measuring a primary current, and detecting if an overcurrent condition occurs; and if an overcurrent condition is detected, continuing with step ii); ii) operating the actuator (156; 256) to open the primary switch (153; 253); iii) detecting if the primary switch (153; 253) is effectively open; and if it is detected that the primary switch is still closed, blowing the fuse (158; 258).