The lack of utility power supply in Nigeria for many hours on daily basis has made individuals and organizations seek
alternative power supplies in form of generating sets and solar system. A solar photovoltaic(PV) system can be utilised to
supply DC power to low power-consuming devices such aslamps in a building while other devices are ACoperated.
Utilising AC power and DC in the same building requires a mains distribution fuse board to distribute AC and
DC power simultaneously. An AC/DC distribution fuse board has been designed to have two power inputs: 220 V mains
supplying an 8-way set of circuit breakers protected by a 60 A MCB and a 12 V DC from solar PV system protected by DC
circuit breakers. The consumer unit has a rectification section where 220 V AC is converted to 12 V DC to supply power to
a DC illumination system. An automatic selection of DC supply to the lighting circuits was provided with a 220 V, 10 A,
AC relay. When mains is available, it supplies power to the lighting circuits and all other AC devices and when not
available, the PV system takes over the supply to the lighting circuits only.