In the US (NEC), standard 120V/240V single-phase wiring uses Black and Red for ungrounded (hot) conductors, White or Gray for grounded (neutral) conductors, and Green, Green/Yellow, or Bare Copper for equipment grounding. In the EU/UK (IEC 60446), the standard is Brown and Black for line, Blue for neutral, and Green/Yellow for earth. However, color alone does not dictate safe installation; you must pair color codes with the correct ampacity and temperature ratings for your specific terminations and raceway fill.
How to Read the Electrical Wire Color Code & Ampacity Chart
A standalone color chart is useless if the wire melts at the breaker terminal. The master table below combines NFPA 70 National Electrical Code (NEC) color requirements with the ampacity values from NEC Table 310.16 for copper conductors.
Use the 75°C column to determine the maximum breaker size and termination ampacity (per NEC 110.14(C), as most residential breakers and receptacles are rated for 75°C). Use the 90°C column exclusively as your starting point for applying temperature and bundling derating factors, before checking the final result against the 75°C termination limit.
How derating rows modify the base value: If you pull more than three current-carrying conductors through a single conduit, the NEC bundling derating tables apply. For example, if you pull four to six current-carrying conductors (like two separate 120V circuits sharing a neutral in a multi-wire branch circuit, plus the neutral), you must multiply the 90°C base ampacity by 80% (0.80). If the derated 90°C value drops below the 75°C termination limit, you must upsize the wire.
Master Electrical Wire Color Code Chart (NEC & IEC Standards)
Bookmark-friendly quick-jump: 12 AWG (standard 20A receptacles) and 10 AWG (standard 30A dryers/RVs) are the most queried rows for residential branch circuits. Note that while 14 AWG has a 75°C ampacity of 15A, NEC 240.4(D) strictly limits its overcurrent protection to 15A regardless of the 90°C column.
US NEC Single-Phase & 3-Phase AC Color Codes (Copper THHN/THWN-2)
| AWG Size | 75°C Ampacity (Termination) | 90°C Ampacity (Derating Base) | Standard Hot Colors (120/240V) | Neutral & Ground Colors |
|---|---|---|---|---|
| 14 AWG | 15A (240.4(D) Limit) | 25A | Black | White / Bare or Green |
| 12 AWG | 20A (240.4(D) Limit) | 30A | Black, Red | White / Bare or Green |
| 10 AWG | 30A (240.4(D) Limit) | 40A | Black, Red | White / Bare or Green |
| 8 AWG | 50A | 55A | Black, Red | White / Bare or Green |
| 6 AWG | 65A | 75A | Black, Red | White / Bare or Green |
| 4 AWG | 85A | 95A | Black, Red, Blue (3-Phase) | White / Bare or Green |
IEC 60446 / UK / EU AC Power Color Codes
For readers working across the pond or wiring imported International Electrotechnical Commission (IEC) compliant machinery, the color standards shifted in the early 2000s to harmonize across Europe.
| Function | Single-Phase | 3-Phase L1 | 3-Phase L2 | 3-Phase L3 | Neutral (N) | Earth (PE) |
|---|---|---|---|---|---|---|
| IEC Color | Brown | Brown | Black | Gray | Blue | Green/Yellow |
What This Chart Cannot Tell You (Edge Cases & Local Code)
A reference chart assumes a standard, straightforward circuit. It cannot account for the specific exceptions and re-identification rules that trip up even experienced DIYers on the jobsite.
- Switch Loops: In a standard switch loop (power to the light fixture, then down to the switch), the white wire traveling down to the switch is actually being used as an ungrounded (hot) conductor. The NEC requires you to permanently re-identify this white wire with black tape or marker at both ends. Do not rely on the white jacket to mean 'neutral' in a switch box.
- 3-Way and 4-Way Travelers: The NEC does not mandate a specific color for traveler wires between multi-way switches. While yellow and blue THHN are the industry standard for travelers to keep them visually distinct from line and load conductors, you will frequently see red and black used. Always trace or test travelers with a multimeter; never assume their function based on color alone.
- Multi-Wire Branch Circuits (MWBC): If you are sharing a neutral (white) between two hot legs (black and red) on a 240V split-phase system, the two hot legs must be on opposite phases (240V between them). If they are accidentally placed on the same phase in the panel, the neutral wire will carry the sum of both loads instead of the difference, leading to a melted neutral and a potential fire.
- DC Systems (Solar/Battery): While the NEC (Article 690) suggests black for positive and white/gray for negative in grounded DC systems, the broader electronics and automotive industries almost universally use Red for DC Positive and Black for DC Negative. Always verify DC polarity with a meter before connecting inverters or charge controllers, as mixing AC and DC color conventions is a frequent cause of bricked equipment.
Frequently Asked Questions
What is the standard electrical wire color code chart for 240V appliances?
For standard US residential 240V appliances (like electric dryers, ranges, and water heaters) that do not require a neutral, you will typically use a 2-conductor cable with a ground (e.g., 10/2 NM-B). The two hot conductors are Black and White. Because the white wire is being used as a hot leg in this specific 240V-only application, the NEC requires you to wrap the white wire in black or red electrical tape at both the panel and the appliance terminal to re-identify it as an ungrounded conductor. If the appliance requires 120V for control boards (like a modern dryer), you will use a 3-conductor cable (10/3 NM-B) containing Black (Hot 1), Red (Hot 2), White (Neutral), and Bare (Ground).
Does the electrical wire color code chart apply to old knob-and-tube wiring?
No. If you are opening up walls in a pre-1950s home, you will encounter knob-and-tube or early cloth-sheathed wiring. Early wiring did not follow modern color codes; you will frequently find both the hot and neutral wires covered in identical black or white cloth braiding, or faded rubber insulation where the original colors have turned uniformly brown or gray. Furthermore, knob-and-tube lacks an equipment grounding conductor entirely. You must treat every wire in an older system as potentially energized until verified dead with a non-contact voltage tester and a digital multimeter. Upgrading these circuits requires pulling new NM-B or THHN in conduit to modern code standards.
How do I read the electrical wire color code chart for 3-phase commercial panels?
In the US, 3-phase color coding depends heavily on the voltage and the specific phase configuration (Wye vs. Delta), but a common high-leg delta (240V) or standard 208Y/120V system follows a specific sequence. For standard 208Y/120V Wye systems, the phases are typically Black (Phase A), Red (Phase B), and Blue (Phase C), with White for neutral and Green for ground. However, in a 240V High-Leg Delta system, Phase B (the high leg or 'wild leg') measures 208V to ground instead of 120V. The NEC (110.15) strictly mandates that this high leg must be identified by an Orange outer finish. If you are pulling wire for a commercial subpanel, always verify the phase sequence and voltage-to-ground with a meter before terminating, as landing a 120V circuit on an orange high-leg will instantly destroy the connected equipment.
