The United States National Electrical Code (NEC) mandates specific colors for 120/240V AC branch circuits: Black or Red for ungrounded (hot) conductors, White or Gray for grounded (neutral) conductors, and Bare Copper or Green for equipment grounding conductors. In Europe and regions following the IEC 60446 standard, the standard single-phase colors are Brown (hot), Blue (neutral), and Green/Yellow (ground). Always verify the standard applicable to your region before terminating any conductors.
How to Read the Electrical Wiring Color Chart
Before pulling wire or terminating a receptacle, you need to understand how to read the reference tables below. The primary columns map the Conductor Function to the required NEC Color and IEC Color. However, professional electricians also look at the Insulation Temperature Rating Context column.
While the temperature rating (60°C, 75°C, or 90°C) does not change the physical color of the wire insulation, it dictates which ampacity column you must reference in NEC Table 310.16 when sizing the breaker for that colored wire. For example, standard NM-B (Romex) cable uses 90°C THHN conductors internally, but NEC Article 334.80 requires you to use the 60°C column for ampacity limits because the overall cable assembly is only rated for 60°C. Conversely, individual THHN wires pulled through conduit allow you to use the 90°C column for derating calculations, even though the final termination at a standard 15A or 20A receptacle is limited to the 60°C or 75°C rating of the device.
Standard Conductor Color Codes (NEC & IEC)
The following spec-sheet-table covers the most common residential and light-commercial AC and DC applications. We have included bookmark-friendly quick-jump rows for the most queried values: Ground, Neutral, and Line/Hot.
| Conductor Function | NEC Color (US/Canada) | IEC Color (UK/EU/AU) | Insulation Temp Rating Context |
|---|---|---|---|
| Equipment Ground | Bare Copper, Green, or Green/Yellow | Green/Yellow Stripe | N/A (Fault current path, not continuous load) |
| Grounded Neutral | White or Natural Gray | Blue (Light Blue for 120V) | Must match hot conductor temp rating (e.g., THHN 90°C) |
| Ungrounded Hot (Line 1) | Black | Brown | Determines breaker size via NEC 310.16 columns |
| Ungrounded Hot (Line 2 / 240V) | Red | Black (or Brown for 3-phase L2) | Used for 240V appliances or 3-way switch travelers |
| Switched Leg / Traveler | Red, Black, or Blue (re-identified) | Brown, Black, or Gray | Must be re-identified with black tape if using white wire |
| 3-Phase A, B, C (208V/480V) | Black, Red, Blue (208V) Brown, Orange, Yellow (480V) |
Brown, Black, Gray | High-leg delta (Orange) must be the B phase |
| DC Positive (+) | Red (ungrounded) or White (grounded) | Brown | Solar PV and battery banks follow NEC 690 / 480 |
| DC Negative (-) | Black (ungrounded) or White (grounded) | Blue | Must be clearly marked if using non-standard colors |
Large Feeder Phase Taping and Ampacity Derating
When you move beyond standard branch circuits (typically 14, 12, and 10 AWG) and start pulling large feeder wires (6 AWG and larger) through conduit, manufacturers generally only sell these in black, gray, or white. To comply with the NFPA 70 (NEC) phase identification rules, electricians use colored phase tape (e.g., red and blue tape on black wires) at every termination point and splice box to create a compliant electrical wiring color chart in the field.
Furthermore, when pulling multiple colored conductors through a single raceway, the base ampacity of the wire must be adjusted. The derating rows in NEC Table 310.15(C)(1) modify this base value by applying a percentage multiplier based on the number of current-carrying conductors.
| Number of Current-Carrying Conductors | Derating Factor (Multiplier) | Example: 12 AWG THHN (Base 30A at 90°C) |
|---|---|---|
| 1 to 3 | 100% | 30A (No modification to base value) |
| 4 to 6 | 80% | 24A (30A × 0.80) |
| 7 to 9 | 70% | 21A (30A × 0.70) |
| 10 to 20 | 50% | 15A (30A × 0.50) |
What This Chart Cannot Tell You
While a standard electrical wiring color chart is essential for identifying conductor function, it has strict limitations on the jobsite:
- Wire Gauge and Ampacity: Color tells you the function, not the size. A black wire could be 14 AWG (15A) or 2/0 AWG (200A). You must read the printed text on the cable jacket or use wire strippers with AWG gauges to verify size.
- Voltage Drop: The chart does not account for distance. A correctly colored 12 AWG wire on a 50-foot run is fine, but on a 150-foot run to a detached garage, you must upsize to 10 AWG or 8 AWG to prevent voltage drop below the 3% NEC recommendation.
- Local AHJ Amendments: Your local Authority Having Jurisdiction (AHJ) may have specific amendments. For example, some municipalities require orange tape on the white neutral wire of a Multi-Wire Branch Circuit (MWBC) to indicate it is carrying unbalanced return current from two different phases.
- Switched Leg Re-identification: If a DIYer used 14/2 NM-B cable to wire a switch loop, the white wire is actually acting as a hot. The NEC requires this white wire to be permanently re-identified with black or red tape at both ends. A color chart won't warn you about missing tape on a legacy switch loop.
Electrical Wiring Color Chart FAQ
Can I use black electrical tape to re-identify a white neutral wire as a hot?
Yes, but only under specific conditions outlined in NEC Article 200.7(C). If you are using a cable assembly (like 14/2 NM-B) for a switch loop, the white wire can be used as the ungrounded (hot) switched leg, provided you permanently wrap it with black or red electrical tape (or heat shrink) at every point the insulation is visible (the panel, the switch box, and the light fixture box). However, you cannot use a white wire as a hot if you are pulling individual THHN conductors through a conduit; in conduit, you must simply pull a correctly colored black or red wire from the start.
What color is the ground wire in older pre-1960s homes?
In homes built before the 1960s (before the NEC mandated equipment grounding conductors in standard branch circuits), you will often find 2-wire NM cable that has no ground wire at all. The cable will only contain a black (hot) and a white (neutral) wire, sometimes with a paper wrap and no outer plastic jacket. If you are upgrading these circuits, you cannot simply rely on the metal conduit or the bare copper wrap as a reliable ground without testing the impedance. According to OSHA and NEC safety guidelines, the safest modern approach is to either pull a new 3-wire cable with a bare copper ground, or install a GFCI receptacle marked "No Equipment Ground" to provide shock protection without a physical ground wire.
Does the electrical wiring color chart apply to low-voltage thermostat or doorbell wires?
No. The NEC color codes detailed above apply to line-voltage AC power (typically over 50V). Low-voltage control wiring, such as 18 AWG or 20 AWG thermostat cables, doorbell wires, and HVAC control boards, follow manufacturer-specific conventions rather than strict NEC color mandates. For example, in standard HVAC thermostat wiring, 'R' is usually Red (24VAC power), 'W' is White (Heat), 'Y' is Yellow (Cooling), and 'G' is Green (Fan). Always refer to the control board schematic rather than the NEC color chart when terminating low-voltage control circuits.
