The standard EU wiring color code follows the IEC 60446 standard (adopted regionally as CENELEC HD 308 S2). For single-phase systems, Line is Brown, Neutral is Blue, and Protective Earth is Green/Yellow. For 3-phase systems, the lines are Brown, Black, and Grey. These harmonized colors apply across all European Union member states and the UK (since 2006).
The Complete EU Wiring Color Code Table (IEC 60446)
Use this spec-sheet table as your primary bench and jobsite reference. It maps the current harmonized EU colors against legacy UK colors and North American (NEC) equivalents to prevent cross-wiring errors when working on imported equipment or older properties.
| Function | Symbol | Current EU (IEC 60446) | Old UK (Pre-2006) | US/NEC (For Contrast) |
|---|---|---|---|---|
| Single-Phase Line | L | Brown | Red | Black |
| Neutral | N | Blue | Black | White / Grey |
| Protective Earth | PE | Green/Yellow Stripe | Green (or bare) | Green / Bare |
| 3-Phase Line 1 | L1 | Brown | Red | Black |
| 3-Phase Line 2 | L2 | Black | Yellow | Red |
| 3-Phase Line 3 | L3 | Grey | Blue | Blue |
Regional Variants: Harmonized EU vs. Old UK vs. North America
While the EU wiring color code is highly standardized today, historical variants remain a major hazard in the field. The most significant regional shift occurred in the UK. In 2006, the UK amended BS 7671 (the IET Wiring Regulations) to align with the European IEC 60446 harmonized colors. According to the UK Health and Safety Executive (HSE), any fixed wiring installed after March 31, 2006, must use the Brown/Blue/Green-Yellow scheme. However, millions of pre-2006 UK homes still contain the old Red (Line) and Black (Neutral) cables.
Which standard applies to you?
- Mainland Europe & Post-2006 UK: Strictly follow IEC 60446 / HD 308 S2. Use NYM-J cable for fixed indoor wiring and H07V-K for panel wiring.
- Pre-2006 UK Properties: Expect a mix. If you are extending an old circuit, you must use the new EU colors but place a permanent warning notice at the consumer unit (breaker panel) stating that both old and new color codes are present.
- Imported US Appliances (NEC): North America follows NFPA 70 (NEC), where Black is Line and White is Neutral. Never assume a US-manufactured appliance's internal wiring matches EU wall colors. Always verify the terminal block markings (L/N/PE) before connecting a replacement EU power cord.
Rows People Get Wrong (And How to Fix Them)
Even experienced electricians make assumptions based on wire color. Here are the most common field errors and how to resolve them safely.
1. The 'Black Wire' Identity Crisis
Black is the most dangerous color to assume. In the current EU 3-phase standard, Black is L2 (a live 400V conductor). In the old UK standard, Black was Neutral. In the US NEC standard, Black is Single-Phase Line. If you open a junction box and see a black wire, never assume its function based on region alone.
The Fix: De-energize the circuit. Use a CAT III or CAT IV multimeter in continuity mode to check if the black wire bonds to the earth bus (indicating a misused earth or a neutral in an old UK setup). Then, energize and carefully test for AC voltage relative to a known earth to confirm if it is a live phase.
2. Faded or Missing Green/Yellow Earth Markings
In older installations, or in high-heat environments like boiler rooms, the yellow stripe on the Protective Earth (PE) wire can fade, bleach, or melt away, leaving what looks like a solid green or bare copper wire. Solid green is not a valid current EU color and indicates either severe degradation or a pre-1970s legacy earth.
The Fix: Do not simply wrap it in electrical tape, which degrades over time. Slide a 4mm or 6mm green/yellow heat-shrink sleeve over the conductor and apply heat to permanently re-identify it to IEC 60446 standards before terminating it in the earth block.
3. Switched Lives in Lighting Circuits
In EU lighting circuits, the wire traveling from the switch to the light fixture (the switched live) is often just another brown wire. This creates a hazard because a worker might assume the brown wire at the ceiling rose is a permanent live, when it is actually only live when the wall switch is ON.
The Fix: Best practice dictates that the switched live should be sleeved with a brown or black marker sleeve at both the switch and the ceiling rose to indicate it is a line conductor, but distinct from the permanent feed. If you find an unsleeved brown wire at a light fixture, test it with a non-contact voltage tester while toggling the wall switch to confirm its switched status.
Frequently Asked Questions
What is the EU wiring color code for a 3-phase supply?
For a standard 400V 3-phase supply in the EU, the color code is: Brown for Line 1 (L1), Black for Line 2 (L2), Grey for Line 3 (L3), Blue for Neutral (N), and Green/Yellow for Protective Earth (PE). The phase sequence (L1-L2-L3) is critical for 3-phase motors; swapping Brown and Grey will reverse the motor's direction of rotation.
Can I use US-colored wire (black/white/green) in an EU installation?
No. Using NEC-colored wire in a fixed EU installation violates IEC 60446 and local wiring regulations (like BS 7671 in the UK or VDE 0100 in Germany). It creates a severe shock hazard for future maintenance workers who expect Blue to be neutral and Brown to be live. You must use harmonized EU cable types (such as H07V-K for single-core panel wiring or NYM-J for fixed structural wiring). The only exception is internal wiring within a manufactured appliance, which is governed by the appliance's specific IEC 60335 product standard.
How do I safely identify wires if the EU color codes are faded or painted over?
If wires are painted over or severely faded, visual identification is invalid and dangerous. Follow this decision path: 1. De-energize the circuit at the main breaker and verify dead with a proven voltage tester. 2. Use a multimeter in continuity mode to identify the Protective Earth (PE) by testing each wire against a known grounded metal pipe or the main earth terminal. 3. Use continuity to identify the Neutral (N) by testing against the neutral bar in the distribution board (if accessible). 4. Re-energize the circuit and use a CAT III multimeter to measure AC voltage between the remaining unidentified wires and the confirmed Earth. The wire reading ~230V is your Line (L). Once identified, turn the power back off and apply fresh, correctly colored heat-shrink sleeving to all conductors before terminating.
