... .2. Standards: BS7211, EN 50268, BS EN 50267-2-1, EN 50267, EN 50265, IEC 603323. Construction: Conductor: ... to BS EN 60228:2005 (previously BS6360) Class 1 solid: 1.5mm² and 2.5mm² Class 2 stranded: 4 ... compacted: 16.0mm² Circuit Protection Conductor (Earth): Class 1 solid plain copper conductor: 1.0mm², 1.5mm², 2.5mm², 4mm² and 6mm² ... Plain 3 Cores: Brown, Black, Grey + Plain PVC insulated earth wire