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🌈 GUIDE

Colors and marking of wires

Wire color guide in electrical engineering according to IEC 60446, IEC and IEC 60364. Reverse search by color — find out if it's phase, neutral, or ground.

📋 Standard selection

Conductor colors

L1Brown
L2Black
L3Gray
NBlue
Neutral conductor
PEYellow-Green
Protective earth. Prohibited from use as a phase conductor.
PENBlue + Yellow-Green markings
Blue throughout, yellow-green markings at ends. TN-C system.

🔍 Reverse search

What wire color do you see?

⚖️ Standard comparison

ConductorIEC/ENSovietNEC (USA)
Phase 1
Brown
Wh/Br
Black
Phase 2
Black
Red
Phase 3
Gray
Blue
Neutral (N)
Blue
Bl/Blk
White
Ground (PE)
Y-G
Y-G/Blk
Green

🛡️ Protective earth PE

Yellow-green stripes at a 45° angle. The only color reserved exclusively for PE.
⚠️ It is strictly forbidden to use yellow-green wire for any purpose other than PE/PEN.

💡 Important nuances

🏗️In older buildings, wire colors may not conform to any standard — always verify with a multimeter
🔵Blue wire in modern wiring — always neutral (N). In old wiring — may be phase
🇺🇦IEC 60446:2007 establishes conductor colour coding and is widely adopted for new electrical installations across Europe and beyond
🔄When working with imported equipment — verify the marking standard in the product documentation

Color marking of wires and phases in Ukraine

Since 2011, Ukraine has adopted a standard corresponding to international standard IEC 60446. According to this standard: phase conductors L1/L2/L3 — brown, black, grey; neutral (N) — blue; protective earth (PE) — yellow-green striped.

In older residential buildings, Soviet-era wiring with different markings or without a PE conductor is often found. Before any work on such wiring, always check each wire with a multimeter.

When working with imported equipment from the USA or Canada, consider the NEC standard, where colors differ drastically: black — phase, white — neutral, green — ground.

When designing an electrical panel, it is important to correctly mark all connections according to IEC. In the ElectroBoard constructor all connections automatically receive correct color marking according to IEC. The system shows brown, black, and grey for phases, blue for neutral, and yellow-green for PE.

For three-phase circuits, it is important to maintain phase sequence: L1 (brown), L2 (black), L3 (grey). This avoids errors during connection and maintenance. In the ElectroBoard constructor, you can verify the correct marking of all connections in the panel.

Frequently asked questions about wire colors

What do wire colors mean in IEC 60446?+
Under IEC 60446: L1 — brown, L2 — black, L3 — gray. Neutral (N) — blue, protective earth (PE) — yellow-green striped.
How do I tell neutral from earth if both look blue?+
Under IEC 60446, neutral (N) is solid blue, PE is yellow-green striped — visually distinct. Problems arise in old Soviet wiring where PE could be black or absent. Always verify with a multimeter.
Is brown always the phase wire?+
In IEC 60446 wiring: L1 is brown, L2 is black, L3 is gray, neutral is blue. Blue is always neutral, never phase in modern wiring. In older Soviet installations colors can be inconsistent — always measure before touching.
Why do wire colors in old buildings differ?+
Soviet wiring (pre-2000s) used a different standard: phase — white or brown, neutral — blue or black. In most old apartments the PE conductor is absent or bonded to neutral (PEN).
Can yellow-green wire be used as phase?+
Absolutely not. Yellow-green is reserved exclusively for PE (protective earth) per IEC 60446 and IEC 60364. Using it as phase creates a lethal hazard during maintenance.
What color is the PEN conductor?+
PEN is marked blue throughout with yellow-green markings at the ends. It is used in TN-C systems, which are prohibited for new residential installations under IEC 60364.
What are the phase colors L1, L2, L3 per IEC 60446?+
Per IEC 60446: L1 — brown, L2 — black, L3 — gray. Maintain phase sequence when installing three-phase circuits. For single-phase systems (most residential), only L1 (brown) is used.

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ElectroBoard automatically applies wire color marking according to IEC when designing a panel.

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