A retrofit lighting system is provided comprising a power supply assembly configured to convert an AC input voltage into a DC output voltage and to adapt the DC output voltage to a substantially constant current level to be defined as a regulated current, at least one distribution wire in electrical communication with the power supply assembly and configured to conduct the regulated current, and at least one respective luminaire assembly spaced apart from and in electrical communication with the power supply assembly, and configured to receive the regulated current from the at least one distribution wire. The DC output voltage may be about 12 volts or less.