A power supply of the present invention comprises a transducer having a transducer and a voltage regulator. The transducer is coupled to an electrically non-conductive medium, which may be a light pipe. The electrically non-conductive medium is coupled to a non-electrical energy source such as a light source and the non-electrical energy source communicates energy to the transducer via said electrically non-conductive medium. The transducer converts the received light energy to electrical energy, which is supplied to a voltage regulator. The voltage regulator has a regulator ground, regulator output, and regulator input. The regulator input is electrically coupled to the transducer output and the regulator ground is electrically coupled to a live conductor of a medium voltage power line. The regulator output therefore provides an output voltage that is ground referenced to the live conductor of the medium voltage power line.