A self-powered current sensing switch with digital setpoint comprising: a current transformer operative to develop an alternating current output, wherein the current transformer includes a core and an induction coil wound around the core; an alternating-current-to-direct-current (AC/DC) converter having an input coupled to the AC output of the current transformer and having a direct current output; an analog-to-digital (A/D) converter coupled to the AC output of the current transformer; a digital processor powered by the DC output of the AC/DC converter and having an input coupled to an output of the A/D converter; an electrically controlled output switch coupled to an output of the digital processor; a manually controlled input switch coupled to the digital processor and having a switch mode position and a calibration mode position; and digital memory ( 52, 54, 56) coupled to the digital processor including code segments executable on the digital processor for: a) performing initialization routines in response to the powering-up of the digital processor by the AC/DC converter; b) operating in a switch mode which is operative to electrically control the output switch based upon a stored digital setpoint when the manually controlled input switch is in the switch mode position; and c) operating in a calibration mode by storing a digital setpoint corresponding to a setpoint current detected by the current transformer when the manually controlled input switch is in the calibration mode position by i. flowing a setpoint current through a wire extending through the core; ii. converting the AC output of the current transformer by means of the A/D converter a digital signal; iii. calculating, on the digital processor, a digital setpoint value from the digital signal; and iv. storing, by the digital processor, the digital setpoint value in non-volatile memory. a current transformer operative to develop an alternating current output, wherein the current transformer includes a core and an induction coil wound around the core; an alternating-current-to-direct-current (AC/DC) converter having an input coupled to the AC output of the current transformer and having a direct current output; an analog-to-digital (A/D) converter coupled to the AC output of the current transformer; a digital processor powered by the DC output of the AC/DC converter and having an input coupled to an output of the A/D converter; an electrically controlled output switch coupled to an output of the digital processor; a manually controlled input switch coupled to the digital processor and having a switch mode position and a calibration mode position; and digital memory ( 52, 54, 56) coupled to the digital processor including code segments executable on the digital processor for: a) performing initialization routines in response to the powering-up of the digital processor by the AC/DC converter; b) operating in a switch mode which is operative to electrically control the output switch based upon a stored digital setpoint when the manually controlled input switch is in the switch mode position; and c) operating in a calibration mode by storing a digital setpoint corresponding to a setpoint current detected by the current transformer when the manually controlled input switch is in the calibration mode position by i. flowing a setpoint current through a wire extending through the core; ii. converting the AC output of the current transformer by means of the A/D converter a digital signal; iii. calculating, on the digital processor, a digital setpoint value from the digital signal; and iv. storing, by the digital processor, the digital setpoint value in non-volatile memory. a) performing initialization routines in response to the powering-up of the digital processor by the AC/DC converter; b) operating in a switch mode which is operative to electrically control the output switch based upon a stored digital setpoint when the manually controlled input switch is in the switch mode position; and c) operating in a calibration mode by storing a digital setpoint corresponding to a setpoint current detected by the current transformer when the manually controlled input switch is in the calibration mode position by i. flowing a setpoint current through a wire extending through the core; ii. converting the AC output of the current transformer by means of the A/D converter a digital signal; iii. calculating, on the digital processor, a digital setpoint value from the digital signal; and iv. storing, by the digital processor, the digital setpoint value in non-volatile memory. i. flowing a setpoint current through a wire extending through the core; ii. converting the AC output of the current transformer by means of the A/D converter a digital signal; iii. calculating, on the digital processor, a digital setpoint value from the digital signal; and iv. storing, by the digital processor, the digital setpoint value in non-volatile memory.