The direct answer for standard US branch circuit wiring (per NEC 200.6, 210.5, and 250.119) is Black, Red, or Blue for ungrounded (hot) conductors, White or Gray for grounded (neutral) conductors, and Green, Green/Yellow, or Bare for equipment grounding conductors. For international installations governed by IEC 60446, the standard shifts to Brown, Black, or Gray for line conductors, Blue for neutral, and Green/Yellow for protective earth.
However, identifying the insulation color is only half the battle on the jobsite. A proper wire chart must also map those colors to the correct American Wire Gauge (AWG) and ampacity limits based on your termination temperature ratings. Below is the definitive reference for matching wire color codes to ampacity and derating factors.
How to Read the Master Wire Chart (Color & Ampacity)
Before pulling wire, you need to understand which column applies to your specific installation. The National Electrical Code (NEC) publishes ampacity tables based on three primary temperature columns: 60°C, 75°C, and 90°C.
How derating rows modify the base value: When you pull multiple current-carrying conductors through a single raceway, heat builds up. If you run four 12 AWG THHN hot/neutral wires in one conduit, you apply the 80% derating factor to the 90°C base ampacity (30A × 0.80 = 24A). Because 24A exceeds the standard 20A breaker limit for 12 AWG wire under NEC 240.4(D), you must either upsize to 10 AWG or split the circuits into separate conduits.
The Master Wire Chart: Color Codes, Ampacity, and Derating
The following spec-sheet-table combines the most critical data points from NFPA 70 (NEC) Table 310.16 and IEC 60446 color standards. This assumes copper conductors in an ambient temperature of 30°C (86°F).
| AWG Size | 60°C Ampacity (Terminations ≤100A) | 75°C Ampacity (Terminations >100A) | 90°C Ampacity (Derating Base) | 4-6 Conductor Derating Factor | US Color (THHN/THWN-2) | EU/UK Color (IEC 60446) |
|---|---|---|---|---|---|---|
| 14 AWG | 15A * | 20A * | 25A | 80% | Black / White / Green | Brown / Blue / Grn-Yel |
| 12 AWG | 20A * | 25A * | 30A | 80% | Black / White / Green | Brown / Blue / Grn-Yel |
| 10 AWG | 30A * | 35A * | 40A | 80% | Black / White / Green | Brown / Blue / Grn-Yel |
| 8 AWG | 40A | 50A | 55A | 80% | Black / Red / White / Grn | Brn / Blk / Blu / Grn-Yel |
| 6 AWG | 55A | 65A | 75A | 80% | Black / Red / White / Grn | Brn / Blk / Blu / Grn-Yel |
| 4 AWG | 70A | 85A | 95A | 80% | Black / Red / White / Grn | Brn / Blk / Blu / Grn-Yel |
| 3 AWG | 85A | 100A | 115A | 80% | Black / Red / White / Grn | Brn / Blk / Blu / Grn-Yel |
| 2 AWG | 95A | 115A | 130A | 80% | Black / Red / White / Grn | Brn / Blk / Blu / Grn-Yel |
| 1 AWG | 110A | 130A | 145A | 80% | Black / Red / White / Grn | Brn / Blk / Blu / Grn-Yel |
| 1/0 AWG | 125A | 150A | 170A | 80% | Black / Red / White / Grn | Brn / Blk / Blu / Grn-Yel |
| 2/0 AWG | 145A | 175A | 195A | 80% | Black / Red / White / Grn | Brn / Blk / Blu / Grn-Yel |
| 3/0 AWG | 165A | 200A | 225A | 80% | Black / Red / White / Grn | Brn / Blk / Blu / Grn-Yel |
| 4/0 AWG | 195A | 230A | 260A | 80% | Black / Red / White / Grn | Brn / Blk / Blu / Grn-Yel |
* Note: NEC 240.4(D) strictly limits standard overcurrent protection for 14 AWG to 15A, 12 AWG to 20A, and 10 AWG to 30A, regardless of the 75°C or 90°C ampacity columns.
Quick-Jump Reference: Most Queried Wire Colors & Sizes
Bookmark this section for the most common residential and light-commercial branch circuits. These assume standard single-phase 120V/240V NM-B (Romex) or THHN in conduit.
- 15A Lighting/Receptacle Circuit: 14 AWG. US Colors: Black (Hot), White (Neutral), Bare (Ground). Breaker: 15A single-pole.
- 20A Kitchen/Bath/Basement Circuit: 12 AWG. US Colors: Black (Hot), White (Neutral), Bare (Ground). Breaker: 20A single-pole (or GFCI/AFCI as required).
- 30A Dryer / RV Receptacle (120/240V): 10 AWG. US Colors: Black (Hot 1), Red (Hot 2), White (Neutral), Green (Ground). Breaker: 30A double-pole.
- 50A Range / EV Charger (240V): 6 AWG. US Colors: Black (Hot 1), Red (Hot 2), White (Neutral - if 4-wire), Green (Ground). Breaker: 50A double-pole.
Decision Path: Picking the Right Wire Color and Size
Use this decision-tree-table to terminate your wire selection process with a concrete pick. Do not guess; follow the logic path to the exact material requirement.
| If your installation is... | And the continuous load is... | Then your concrete pick is... |
|---|---|---|
| Standard 120V wall receptacles in a living area | ≤ 12A continuous (15A max) | 14 AWG NM-B 14/2 w/ Ground (Black, White, Bare) on a 15A AFCI breaker. |
| Kitchen small-appliance branch circuit (SABC) | ≤ 16A continuous (20A max) | 12 AWG NM-B 12/2 w/ Ground (Black, White, Bare) on a 20A GFCI/AFCI breaker. |
| 240V baseboard heater or window AC | ≤ 24A continuous (30A max) | 10 AWG THHN (Black, Red, Green) pulled in 1/2' EMT conduit on a 30A double-pole breaker. |
| Level 2 EV Charger (Hardwired) | 40A continuous (requires 125% sizing = 50A) | 6 AWG THHN (Black, Red, Green) in 3/4' EMT on a 50A double-pole breaker. (Do not use 8 AWG; it derates too close to the limit). |
| Main panel to 100A subpanel feeder | 100A max non-continuous | 2 AWG Copper THHN (Black, Red, White, Green) or 1/0 AWG Aluminum XHHW in 1.5' PVC. |
What This Wire Chart Color Guide Cannot Tell You
While this reference covers the baseline NEC and IEC requirements for branch circuits and feeders, a flat table cannot account for every physical variable on the jobsite. Here is what you must calculate separately:
- Voltage Drop: This chart assumes runs under 100 feet. If you are running a 240V circuit to a detached garage 250 feet away, a 6 AWG wire might be legally ampable for a 50A breaker, but it will suffer unacceptable voltage drop. You must upsize to 4 AWG or 3 AWG to keep the drop under the NEC-recommended 3% for branch circuits.
- Ambient Temperature Corrections: The 90°C derating column assumes an ambient temperature of 30°C (86°F). If your conduit is running across a 110°F attic space or buried in thermal insulation, you must apply the ambient temperature correction factors from NEC Table 310.15(B)(1) before applying the bundling derating factor.
- Local AHJ Overrides: Some municipalities have strict amendments regarding wire colors. For example, certain jurisdictions require 277V/480V commercial circuits to use Brown, Orange, and Yellow for hots, while others mandate specific phase-tape markings on white neutrals if they are used as switched legs. Always verify with your local Authority Having Jurisdiction (AHJ) or electrical inspector.
- Appliance-Specific Cords: This chart applies to building wiring (THHN, NM-B, XHHW). It does not apply to factory-molded appliance cords (like a 3-prong vs. 4-prong dryer cord), which follow UL listing requirements rather than field-installed NEC branch circuit rules.
When in doubt, default to the 75°C ampacity column for termination sizing, use the 90°C column strictly for derating math, and always pull a dedicated green or bare equipment grounding conductor rather than relying on metallic conduit alone. For deeper code analysis, consult the Mike Holt Enterprises NEC termination guides to ensure your lugs and wire ratings perfectly align.
