European Wire Color Codes (IEC): AC and DC Wiring for Europe and the UK

Most European countries, including the UK, follow the IEC (International Electrotechnical Commission) wiring color standard. This guide covers European wire color codes for both AC (Alternating Current — mains and wall outlet power) and DC (Direct Current — batteries and electronics) supply wiring, including single-phase, three-phase, and multiple DC configurations.

This article is for reference only. Always refer to local regulations before carrying out any electrical work.

Key Takeaways

• Most European countries follow the IEC wiring color standard for both AC and DC electrical supply.
• For AC supply, the standard colors are: Brown (Line/Hot for single-phase and Line 1 for three-phase), Black (three-phase Line 2), Grey (three-phase Line 3), Blue (Neutral), and Green with Yellow Stripe (Ground).
• For DC supply, Brown is used for Positive, and Grey for Negative in a standard two-wire ungrounded configuration.
• In grounded DC circuits, the color assignment for positive and negative conductors depends on whether the positive or negative conductor is grounded.
• Ground wiring across all configurations (AC and DC) uses the Green with Yellow Stripe color code.

Wiring Color Codes in Europe (IEC) for AC Supply

European IEC wiring color codes for AC supply are as follows:

Single Phase, Line (Hot) – Brown

3 Phase, Line 1 – Brown

3 Phase, Line 2 – Black

3 Phase, Line 3 – Grey

Neutral – Blue

Ground – Green with Yellow Stripe

Wiring Color Codes in Europe (IEC) for DC Supply

DC supply has multiple configurations, and the color assignment for each conductor varies depending on the circuit type.

European IEC wiring color codes for DC supply are as follows:

2 Wire Ungrounded DC Supply

• Positive (+ve) – Brown
• Negative (-ve) – Grey

2 Wire Grounded DC Supply

• Positive (+ve) of Negative (-ve) grounded circuit – Brown
• Negative (-ve) of Negative (-ve) grounded circuit – Blue
• Positive (+ve) of Positive (+ve) grounded circuit – Blue
• Negative (-ve) of Positive (+ve) grounded circuit – Grey

3 Wire Grounded DC Supply

• Positive (+ve) – Brown
• Mid Wire (Center Tap) – Blue
• Negative (-ve) – Grey

Common

• Ground – Green with Yellow Stripe