Direct Answer: For standard US 120V/240V AC residential wiring, Black and Red are hot (line), White is neutral, and Bare copper or Green is ground. For EU/UK IEC 60446 AC wiring, Brown and Black are hot, Blue is neutral, and Green-Yellow is ground. For 12V/24V DC systems globally, Red is positive and Black (or White) is negative. Always verify with a multimeter before touching any conductor.
The Master Wire Color Coding Chart (NEC & IEC Standards)
The following table consolidates the mandatory conductor identification requirements for the US NFPA 70 National Electrical Code (NEC) and the international IEC 60446 standard (adopted across the UK, EU, and Australia).
| Function | US NEC (AC Power) | US NEC (DC Power) | EU/UK IEC 60446 (AC) | EU/UK IEC (DC) |
|---|---|---|---|---|
| Hot / Line 1 (120V / 230V) | Black | Red (or Brown) | Brown | Brown |
| Hot / Line 2 (240V Split Phase) | Red | Black (or Blue) | Black | Grey |
| Hot / Line 3 (3-Phase) | Blue | White (or Yellow) | Grey | Blue |
| Neutral / Grounded Conductor | White or Grey | White or Black w/ White Stripe | Blue | Blue w/ White Stripe |
| Equipment Ground / Earth | Bare, Green, or Green-Yellow | Bare or Green | Green-Yellow | Green-Yellow |
How to Read This Chart and Apply It to Your Installation
Which column applies to you? If you are wiring a home, subpanel, or appliance in the United States, use the US NEC (AC Power) column. If you are building a solar battery bank, off-grid inverter setup, or automotive harness, use the US NEC (DC Power) column. If you are located in Europe, the UK, or working with imported IEC-rated machinery (like certain CNC routers or 3D printers), use the EU/UK IEC columns.
Temperature Ratings and Insulation: While color identifies the circuit's purpose, the insulation jacket (THHN, XHHW, NM-B) dictates the temperature column you use for ampacity. Standard NM-B (Romex) is limited to the 60°C column regardless of the wire color, while individual THHN conductors in conduit can utilize the 90°C column for derating calculations, terminating at 75°C for standard breaker lugs.
Quick-Jump Reference for the Most Queried Circuits
Bookmark these specific configurations for the most common DIY and tradesperson tasks:
- Standard 120V Receptacle (US): Black to Brass screw (Hot), White to Silver screw (Neutral), Bare to Green screw (Ground).
- 240V Electric Dryer/Range (US 4-Prong): Black and Red to outer hot terminals (120V each to neutral), White to center neutral terminal, Bare to chassis ground.
- 3-Way Switch Travelers (US): When pulling 12/3 NM-B cable, use the Red and Black wires as travelers between switches. The White is neutral, and Bare is ground.
- 12V Solar Panel to Charge Controller (DC): Red to Positive (+), Black to Negative (-). Always fuse the Red wire within 6 inches of the battery positive terminal.
- EU Single-Phase 230V Outlet: Brown to Line (L), Blue to Neutral (N), Green-Yellow to Earth (E).
Decision Tree: Which Color Do I Actually Need?
Use this decision path to select the exact wire color or cable type for your next pull. This assumes standard US NEC residential/commercial applications.
| If your circuit is... | And you are pulling... | Then your concrete pick is... |
|---|---|---|
| 120V, 15A or 20A Branch | Non-Metallic Cable (NM-B) | 14/2 or 12/2 NM-B (Contains Black, White, Bare) |
| 240V, 30A+ Appliance (No 120V tap) | Non-Metallic Cable (NM-B) | 10/2 or 8/2 NM-B (Black, White re-identified as Red via tape, Bare) |
| 240V/120V Split Phase (Dryer/Range) | Non-Metallic Cable (NM-B) | 10/3 or 8/3 NM-B (Contains Black, Red, White, Bare) |
| Any circuit in exposed conduit | Individual Conductors (THHN) | Buy spools of Black (Hot), White (Neutral), Green (Ground) |
| Multi-way switch leg (3-way/4-way) | Non-Metallic Cable (NM-B) | 14/3 or 12/3 NM-B (Use Red and Black as travelers) |
What This Chart Cannot Tell You (Edge Cases & Legacy Wiring)
A color chart provides the baseline standard, but real-world jobsites require you to account for manufacturing constraints, code exceptions, and historical wiring. Here is what the chart leaves out:
1. The 'Switch Loop' Exception (NEC 200.7(C)(1))
In older homes (and some modern smart-switch retrofits), you may find a 2-wire cable running from a ceiling light down to a wall switch. The White wire is used to carry hot power down to the switch, and the Black wire carries the switched hot back up. The NEC mandates that if a white wire is used as a hot conductor, it must be re-identified with black or red electrical tape (or paint) at both ends. If you see a white wire with black tape on it, treat it as a hot line, not a neutral.
2. Multi-Conductor Cable Manufacturing Limits
You cannot always buy NM-B cable in custom color combinations. If you need two hot wires and a neutral for a multi-wire branch circuit (MWBC), you must buy 12/3 NM-B. The factory colors are Black, Red, White, and Bare. You cannot order a 12/3 cable with Black, Blue, and White. If you need a Blue wire for a 3-phase run or a specific IEC machine, you must pull individual THHN conductors through conduit, not use NM-B.
3. Legacy and Knob-and-Tube Wiring
If you are working in a home built before 1950, throw this chart out the window. Early rubber-insulated wires were often solid black for both hot and neutral, or used asbestos-wrapped white wires that have yellowed to look identical to the hot wires. Furthermore, early 240V appliances often used 3-wire setups (two hots and a combined neutral/ground) which the NEC banned for new installations in 1996. Always test legacy circuits with a non-contact voltage tester and a multimeter before assuming the color code applies.
4. High-Leg Delta Systems (NEC 215.8 / 230.56)
In older commercial buildings with 240V 3-phase High-Leg Delta service, one of the hot phases measures 208V to ground instead of 120V. The NEC strictly requires this high-leg (usually Phase B) to be identified with Orange insulation. If you open a commercial panel and see an orange wire, do not connect it to a standard 120V breaker; it will destroy the appliance and trip the breaker instantly.
