The colors of wires in low-voltage distribution cabinets in various regions
The following are the commonly used wire color standards in low-voltage distribution cabinets in major countries and regions (based on low-voltage power distribution systems, three-phase/single-phase circuits) for reference:
I. China (GB 7947/IEC 60446)
| Function | Color | Explanation |
| Three-phase live wire (L1) | Yellow (Y) | Phase A (live wire) |
| Three-phase live wire (L2) | Green (G) | Phase B (live wire) |
| Three-phase live wire (L3) 三相火线（L3） | Red (R) | Phase C (live wire) |
| Neutral wire (N) | Blue (B) | Neutral wire (neutral) |
| Ground wire (PE) | Yellow-green two-color (Y/G) | Protective ground wire (PE wire) |
| Single-phase live wire (L) | Red (R) | Live wire in a single-phase circuit |
II. United States (NEC standard, ANSI/NFPA 70)
| Function | Color | Explanation |
| Three-phase live wire (L1) | Black (Bk) | Phase A (live wire) |
| Three-phase live wire (L2) | Red (R) | Phase B (live wire) |
| Three-phase live wire (L3) | Blue (Bl) | Phase C (live wire, 208Y/120V system) |
| Neutral wire (N) | White (W) | Neutral wire (neutral), with stripes or markings |
| Ground wire (PE) | Green (G) or yellow-green two-color | Protective ground wire (bare or insulated) |
| Single-phase live wire (L) | Black (Bk) or Red (R) | Live wire in a single-phase circuit (120V/240V system) |
III. European Union (IEC 60446, taking Germany and France as examples)
| Function | Color | Explanation |
| Three-phase live wire (L1) | Brown (Br) | Phase A (live wire) |
| Three-phase live wire (L2) | Black (Bk) | Phase B (live wire) |
| Three-phase live wire (L3) | Gray (Gy) | Phase C (live wire) |
| Neutral wire (N) | Blue (B) | Neutral wire (neutral) |
| Ground wire (PE) | Yellow-green two-color (Y/G) | Protective ground wire (PE wire) |
| Single-phase live wire (L) | Brown (Br) | Live wire in a single-phase circuit |
IV. United Kingdom (Old standard vs New standard)
- **Old standard (Before 2004, BS 7671)**:
| Function | Color |
| Three-phase live wire | Red (R), Yellow (Y), Blue (Bl) |
| Neutral wire (N) | Black (Bk) |
| Ground wire (PE) | Yellow-green two-color (Y/G) |
- **New standard (After 2004, in line with IEC in the European Union)**:
The same as the EU standard (Live wires: Brown, Black, Gray; Neutral wire: Blue; Ground wire: Yellow-green two-color).
V. Japan (JIS C 3306)
| Function | Color | Explanation |
| Three-phase live wire (L1) 三相火线（L1） | Red (R) | Live wire in a 100V system (Phase A) |
| Three-phase live wire (L2) | Black (Bk) | Live wire in a 100V system (Phase B) |
| Neutral wire (N) | White (W) | Neutral wire (neutral) |
| Ground wire (PE) | Green (G) | Protective ground wire (PE wire) |
| Single-phase live wire (L) | Red (R) or Black (Bk) | Live wire in a single-phase circuit (100V/200V system) |
VI. Other regions
- **Australia/New Zealand (AS/NZS 3000)**:
Live wires: Brown (L1), Blue (L2), Black (L3); Neutral wire: Light blue; Ground wire: Yellow-green two-color.
- **Canada (CSA C22.1)**:
Similar to the US standard, three-phase live wires are commonly black, red, and blue, the neutral wire is white, and the ground wire is green.
- **Russia (GOST standard)**:
Live wires: Yellow (L1), Green (L2), Red (L3); Neutral wire: Light blue; Ground wire: Yellow-green two-color.
Precautions
1. **Differences in standards**: Some countries may retain the old standards due to historical reasons (such as the old version in the UK). It is recommended to refer to the latest local electrical codes.
2. **High-voltage systems**: The colors of wires in high-voltage power distribution may be different (for example, high-voltage live wires in China are red, green, and yellow, and there is no neutral wire). It is necessary to refer to specific engineering standards.
3. **Safety principles**: Regardless of the color, when wiring, it is necessary to confirm the function of the wires through labels, drawings, or a multimeter to avoid misoperation.
For accurate information, it is recommended to consult the local electrical installation codes (such as GB 7251 in China, NEC in the United States, EN 60446 in the European Union, etc.) or consult a professional electrician.
