Unsheathed single core cables cables for fixed installations. Installed in ducts (above ground or recessed) or similar closed systems. They are also suitable for protected fixed installations, lighting and control gear for voltages up to and including 1000V AC or up to and including 750V DC ground. According to the Low Voltage Regulation REBT 2002: ITC-BT-09 ,20, 26, 27, 30, 31, 41.