A switch includes a body with a switch member on a top thereof, an extension extends from an underside of the switch member, and a substantially inverted L-shaped slot is defined through the extension. Two terminals extend through a bottom of the body, in which one of the terminals is fixed with a contact plate. The contact plate has a tongue with a free end, which contacts the other terminal when the circuit is ON, and is separated from the other terminal when the circuit is OFF. An operation member has a first end movably engaged with the slot and a second end connected with the contact plate. Under the current overload condition, the contact plate deforms, the first end of the operation member move downward along the vertical space of the slot, and the switch member is pivoted by a torsion spring to the OFF position.
