A circuit protection device comprising: a substrate comprising a first electrode and a second electrode; a sliding contact positioned on the substrate, wherein: at a first location on the substrate the sliding contact provides a conductive path between the first and second electrodes (124, 126), a sensing element holds the sliding contact at the first location, and at a second location on the substrate the sliding contact does not provide a conductive path between the first and second electrodes (124, 126); and a spring element configured to exert on the sliding contact a force parallel to a length of the substrate, wherein the sliding contact is configured to resist the force when the sliding contact is held at the first location by the sensing element, and wherein upon detection of an activation condition, the sensing element releases the sliding contact and the force exerted by the spring element moves the sliding contact to the second location, characterised in that the sliding contact (108, 302, 810) comprises a cantilever portion (122, 808) against which the spring element (106, 802) exerts the force parallel to the length of the substrate (102, 312), and the cantilever portion (122, 808) extends into a channel (310, 902) defined by one of an opening in the substrate, an opening in an underside of a housing that fits over the substrate, and a depression in an underside of a housing that fits over the substrate and the sliding contact, wherein the cantilever portion (122, 808) is located at a first end of the channel (310, 902) when the sliding contact (108, 302, 810) is at the first location. a substrate comprising a first electrode and a second electrode; a sliding contact positioned on the substrate, wherein: at a first location on the substrate the sliding contact provides a conductive path between the first and second electrodes (124, 126), a sensing element holds the sliding contact at the first location, and at a second location on the substrate the sliding contact does not provide a conductive path between the first and second electrodes (124, 126); and at a first location on the substrate the sliding contact provides a conductive path between the first and second electrodes (124, 126), a sensing element holds the sliding contact at the first location, and at a second location on the substrate the sliding contact does not provide a conductive path between the first and second electrodes (124, 126); and a spring element configured to exert on the sliding contact a force parallel to a length of the substrate, wherein the sliding contact is configured to resist the force when the sliding contact is held at the first location by the sensing element, and wherein upon detection of an activation condition, the sensing element releases the sliding contact and the force exerted by the spring element moves the sliding contact to the second location, characterised in that the sliding contact (108, 302, 810) comprises a cantilever portion (122, 808) against which the spring element (106, 802) exerts the force parallel to the length of the substrate (102, 312), and the cantilever portion (122, 808) extends into a channel (310, 902) defined by one of an opening in the substrate, an opening in an underside of a housing that fits over the substrate, and a depression in an underside of a housing that fits over the substrate and the sliding contact, wherein the cantilever portion (122, 808) is located at a first end of the channel (310, 902) when the sliding contact (108, 302, 810) is at the first location.