Control cabinet wiring in Europe follows EN 60204-1 and IEC 60445 standards, with specific color codes for AC/DC power, control circuits, neutral, and protective earth, while allowing some flexibility for labeling and exceptions.

Standard Color Codes

• Protective Earth (PE): Green-and-yellow bicolor, reserved exclusively for protective earth conductors. This color must be maintained along the entire accessible length, though in some cases marking only at accessible points or ends is acceptable if the conductor is clearly identifiable .
• Neutral Conductor (N): Light blue, used exclusively for neutral wiring to avoid confusion with other circuits .
• AC Main Power Conductors: Black is typically used for AC and DC main power chains .
• AC Control Circuits: Red is recommended for AC control current chains .
• DC Control Circuits: Blue (dark blue) is used for DC control current chains .
• Excepted Circuits / Special Cases: Orange is used for circuits that remain live when the main switch is off, such as potential-free contacts or circuits not requiring separation .

Practical Considerations

• Labeling and Identification: IEC 60445 allows alternative identification methods such as terminal numbering, wire markers, or functional labels. Color coding is not mandatory if conductors are clearly marked .
• Control Cabinet vs External Wiring: NEN-EN-IEC 61439 provides more flexible color coding inside control cabinets compared to strict external installation rules (e.g., NEN 1010). For example, green-yellow for protective earth is recommended but not strictly required if the wire is unambiguously identifiable .
• Multi-core Cables: Exceptions are allowed when insulation in the recommended color is unavailable. In such cases, marking at connection points or using labels is sufficient .
• Connection Practices: Only one protective conductor should connect to a terminal unless the terminal is designed for multiple connections. Conductors should be secured, supported, and clearly identifiable .

Summary

European and international standards provide a consistent framework for wiring color codes in control cabinets, prioritizing safety and traceability. While green-yellow for protective earth and light blue for neutral are mandatory, other colors like black, red, blue, and orange are recommended for power and control circuits. Flexibility exists for labeling, multi-core cables, and internal cabinet wiring, provided that identification remains clear and unambiguous . This ensures compliance with EN 60204-1, IEC 60445, and NEN-EN-IEC 61439 while supporting safe and maintainable installations.