IEC 60173: Flexible Cable Core Colours — How Yellow-Green Became the Universal Earth Wire

Flexible Cable Core Colours — The Origin of the Yellow-Green Earth Wire

IEC 60173 specifies core colours for flexible cables and cords. Every electrical engineer knows: Yellow-Green = Earth/PE, Blue = Neutral (N), Brown/Black/Grey = Phases (L1/L2/L3). This colour code comes directly from IEC 60173.