Single core cables without cover for fixed installations. Installed in ducts (located on surface or recessed) or in similar closed systems. They are also suitable for fixed installations protected, lighting and switchgear control and control for voltages up to 1000V (inclusive) in alternating current or up to 750V with respect to ground in direct current. According to the Low Voltage Regulation REBT 2002: ITC-BT-09 ,20, 26, 27, 30, 31, 41.