DC lighting system

A DC lighting system for a building. The system comprises a DC distribution network, arranged to supply DC power to at least a portion of the building. The system also includes a plurality of DC lights, each light being coupled to the DC distribution network at spaced intervals. The system also includes a DC power source having a DC power output, the DC power source being coupled to the DC distribution network to provide DC power to the plurality of lights. The DC power source is a rechargeable battery. The system also includes a charger, coupled to the DC power source, the charger arranged to charge the DC power source. The system also includes a mains power source, coupled to the charger to provide power to the charger for charging the DC power source. The system also includes a first switching mechanism coupled to the DC distribution network, to switch at least one of said light between an on setting and an off setting.