China Wire Color Code Guide: GB Standards vs IEC & NEC Explained

The modern China wire color code is governed by the GB/T 6995 standard and aligns almost perfectly with the international IEC 60446 standard. For standard AC wiring in China, Phase (Line) is Brown, Black, or Grey; Neutral is Light Blue; and Protective Earth is Green/Yellow. However, if you are troubleshooting older equipment, importing Chinese machinery, or working with DC control circuits, legacy colors and regional variations can create dangerous confusion. Below is the exact reference data you need to wire, test, and verify circuits safely.

The Complete China Wire Color Code Reference Table (GB/T 6995)

This table reflects the current GB/T 6995 (Wires and Cables) and GB 50303 (Building Electrical Construction Quality) standards enforced in China. Use this as your primary reference for modern installations and newly manufactured Chinese electrical panels.

Rows People Get Wrong: Legacy vs. Modern GB Standards

If you open a control panel on a Chinese CNC machine built before 2012, or rewire an older commercial building in Shenzhen, the table above might not match what you see. Here are the specific rows where mistakes happen:

• The Old 3-Phase Trap (Yellow, Green, Red): Prior to harmonizing with IEC, China used Yellow for L1, Green for L2, and Red for L3. If you are retrofitting a panel and see these colors, do not assume Green is ground or earth. In legacy Chinese 3-phase, Green is a live phase conductor carrying full line voltage.
• The DC Negative Confusion (Black vs. Blue): In North America (NEC), DC negative or grounded DC is often Black or White. In modern GB and IEC standards, DC negative is Blue, while Black is reserved for AC Phase 2 (L2). Mixing these up when wiring a 24VDC control circuit to a PLC will instantly fry the inputs.
• Switched Legs and Travelers: GB standards do not strictly mandate colors for 3-way switch travelers or switched hot legs. In practice, Chinese electricians often use Red, Yellow, or White for switched legs. Always test these with a non-contact voltage tester (NCVT) before assuming they are neutrals.

Regional Variants: GB vs. IEC vs. NEC vs. Old UK

Understanding how the China wire color code maps to other global standards is critical when integrating imported machinery into local facilities. For a deeper dive into global harmonization, refer to comprehensive wiring guides like those found on Electrical Technology.

Note: The NFPA NEC standards dictate North American colors. Never connect a machine wired strictly to GB standards directly to a US panel without re-identifying (re-taping) the conductors at the termination points to match NEC color requirements.

Safe Interpretation When Markings Are Faded or Missing

Heat, UV exposure, and cheap PVC insulation can cause Chinese wire colors to fade, turn completely yellowish-brown, or lose their striping. When visual identification fails, follow this bench-and-jobsite proven sequence:

1. Isolate and De-energize: Turn off the main breaker. Lock it out.
2. Continuity Test for Earth: Set your multimeter to continuity/resistance (Ω). Place one probe on the suspected earth wire and the other on a known, unpainted grounded metal chassis or the main earth busbar. A reading of < 1.0 Ω confirms it is the PE (Protective Earth) wire, regardless of its faded color.
3. Neutral Identification: With power still OFF, disconnect the neutral from the busbar. Measure continuity between the suspected neutral and the neutral busbar. It should read near 0 Ω. Measure between this wire and the ground busbar; it should read infinite (OL) if the system is correctly isolated.
4. Live Verification: Once Earth and Neutral are positively identified and safely terminated, restore power. Use a CAT III or CAT IV Non-Contact Voltage Tester (NCVT) to identify the live phase conductors. Follow up with a multimeter measuring Phase-to-Neutral (should read ~220V-240V in China) and Phase-to-Earth (same).

Decision Path: Wiring or Troubleshooting Chinese Equipment

Use this decision tree to determine your exact next step when dealing with Chinese wire color codes on the bench or jobsite.

When in doubt, the physical continuity and voltage measurements always override the insulation color. Keep a reliable multimeter and a roll of 3M Scotch 88 series tape on hand to re-tag any conductor that doesn't match the standard.