A fusible switch disconnect device comprising: a disconnect housing adapted to removably receive and engage at least a portion of a removable overcurrent protection fuse module, the fuse including a fuse housing first and second terminal elements and a fusible element electrically connected therebetween, the fusible element defining a circuit path and being configured to permanently open the circuit path in response to predetermined electrical current conditions experienced in the circuit path; line side and load side terminals (785, 768, 764, 782) in the disconnect housing and electrically connecting to the respective first and second terminal elements of the fuse when the fuse is received and engaged with the disconnect housing; at least one switchable contact (778, 780) in the disconnect housing, the at least one switchable contact provided between one of the line side terminal and load side terminal and a corresponding one of the first and second terminal elements of the fuse, the at least one switchable contact selectively positionable in an open position and a closed position to respectively connect or disconnect an electrical connection between the line side terminal and the load side terminal and through the circuit path of the fusible element; a current detecting element (830, 902, 910) configured to detect current flow associated with the circuit path of the fusible element when the at least one switchable contact is closed; characterised in that the fusible switch disconnect device further comprises circuitry in communication with the current detecting element, the circuitry configured, based on an input from the current detecting element, to assess a magnitude-based and time-based current performance of the fuse relative to a typical magnitude-based and time-based current performance of a properly rated fuse that is compatible with the disconnect housing; and wherein the fuse housing projects from the disconnect housing such that it is open and accessible from the exterior of the disconnect housing to facilitate removal of the fuse including the first and second terminal elements from the disconnect housing and the line side and load side terminals, whereby when the fuse is removed an open circuit is established between the line side and load side terminals. a disconnect housing adapted to removably receive and engage at least a portion of a removable overcurrent protection fuse module, the fuse including a fuse housing first and second terminal elements and a fusible element electrically connected therebetween, the fusible element defining a circuit path and being configured to permanently open the circuit path in response to predetermined electrical current conditions experienced in the circuit path; line side and load side terminals (785, 768, 764, 782) in the disconnect housing and electrically connecting to the respective first and second terminal elements of the fuse when the fuse is received and engaged with the disconnect housing; at least one switchable contact (778, 780) in the disconnect housing, the at least one switchable contact provided between one of the line side terminal and load side terminal and a corresponding one of the first and second terminal elements of the fuse, the at least one switchable contact selectively positionable in an open position and a closed position to respectively connect or disconnect an electrical connection between the line side terminal and the load side terminal and through the circuit path of the fusible element; a current detecting element (830, 902, 910) configured to detect current flow associated with the circuit path of the fusible element when the at least one switchable contact is closed; characterised in that the fusible switch disconnect device further comprises circuitry in communication with the current detecting element, the circuitry configured, based on an input from the current detecting element, to assess a magnitude-based and time-based current performance of the fuse relative to a typical magnitude-based and time-based current performance of a properly rated fuse that is compatible with the disconnect housing; and wherein the fuse housing projects from the disconnect housing such that it is open and accessible from the exterior of the disconnect housing to facilitate removal of the fuse including the first and second terminal elements from the disconnect housing and the line side and load side terminals, whereby when the fuse is removed an open circuit is established between the line side and load side terminals.