6 AWG Wire Ampacity & Specifications
6 AWG copper wire carries 65A at 75°C (NEC Table 310.16), or 50A for aluminum; copper is typically protected by a 60A breaker.
Calculations are built on the 2023 National Electrical Code (NEC) and cross-checked against the published code tables. How we verify. Last updated June 2026.
6 AWG wire has an ampacity of 65A at 75°C for copper and 50A for aluminum (NEC Table 310.16). Its 60°C and 90°C copper ratings are 55A and 75A. Copper 6 AWG is commonly protected by a 60A breaker.
6 AWG Wire Specifications
| Ampacity — Copper (60 / 75 / 90°C) | 55 / 65 / 75 A |
| Ampacity — Aluminum (60 / 75 / 90°C) | 40 / 50 / 55 A |
| Cross-section | 26,240 circular mils |
| DC resistance — Copper | 0.491 Ω / 1000 ft |
| DC resistance — Aluminum | 0.808 Ω / 1000 ft |
| Typical voltage drop (240V) | 1.2% at 50 ft · 2.5% at 100 ft (at 60A) |
6 AWG Ampacity by Wire Type
The same 6 AWG conductor gets a different ampacity depending on the cable type and the terminal rating. "Usable" is the conductor ampacity before ambient or bundling adjustment; how much load the circuit may carry and the breaker size are separate checks (below). Assumes 30 °C ambient and no more than three current-carrying conductors. THHN is rated 90 °C in dry locations; THWN-2 is 90 °C wet or dry; NM-B is for dry locations; UF-B can be direct-buried.
| Wire type | NEC column | Table ampacity | Usable |
|---|---|---|---|
| THHN / THWN-2 copper in conduit | 90 °C table, 75 °C terminals | 75 A | 65 A |
| THW / THWN copper (75 °C) | 75 °C insulation and terminals | 65 A | 65 A |
| NM-B (Romex) copper | 60 °C (NEC 334.80) | 55 A | 55 A |
| UF-B copper | 60 °C (NEC 340.80) | 55 A | 55 A |
| XHHW-2 aluminum | 90 °C table, 75 °C terminals | 55 A | 50 A |
6 AWG Breaker Size: 50, 60 or 70 A?
- Copper THHN/THWN-2 or THWN, 75 °C terminals: 60 A. 65 A is the conductor ampacity, not a standard breaker size (NEC 240.6(A)), so the usual breaker is 60 A.
- Aluminum, 75 °C terminals: 50 A. 6 AWG aluminum is rated 50 A, a standard size, so no rounding applies.
- NM-B (Romex): 50 A circuit. The cable is limited to 55 A; NEC 240.4(B) may allow the next standard device (60 A) for a single, non-receptacle load, but it does not raise the cable's ampacity.
- 70 A on 65 A copper is possible only under the 240.4(B) next-size-up conditions, and the load must still stay within 65 A.
- Continuous loads (3 hours or more) are limited to 80% of the breaker and to the conductor ampacity ÷ 1.25: 48 A on a 60 A copper THHN/THWN-2 circuit, 40 A on a 50 A aluminum circuit, and 44 A on 6 AWG NM-B (55 A ÷ 1.25) even if a 60 A breaker is used.
How Far Can You Run 6 AWG Wire?
Longest one-way run for copper at 3% voltage drop, single-phase: Lmax = 0.03 × V × 1000 / (2 × I × R), with R = 0.491 Ω/1000 ft (NEC Chapter 9 Table 8, uncoated copper at 75 °C). This is a resistance-only estimate; reactance and power factor are not modeled, and 3% is a design target, not a code limit. Each distance opens the calculator with that load (non-continuous, copper, 75 °C terminals).
Example: a 50 A load at 240 V, 100 ft away. 8 AWG carries 50 A but drops more than 3% at that distance, so the calculator picks 6 AWG (2.05% drop). Open this example
6 AWG Ampacity After Derating
THHN/THWN-2 is derated from its 90 °C value (NEC 310.15(B)(1) ambient, 310.15(C)(1) bundling), and the result still cannot exceed the 75 °C terminal rating of 65 A. Ambient means the temperature around the conductor where it runs. Click a row to open it in the ampacity calculator.
| Condition (copper THHN/THWN-2) | Derated | Usable |
|---|---|---|
| 30 °C ambient, 3 conductors | 75.0 A | 65.0 A |
| 40 °C ambient (for example a hot attic), 3 conductors | 68.3 A | 65.0 A |
| 30 °C ambient, 4–6 current-carrying conductors | 60.0 A | 60.0 A |
| 40 °C ambient, 4–6 current-carrying conductors | 54.6 A | 54.6 A |
6 AWG Diameter and Cross-Section
| Bare diameter, solid (AWG definition) | 0.162 in / 4.12 mm |
| Bare diameter, 7-strand (NEC Ch. 9 Table 8) | 0.184 in / 4.67 mm |
| Metal cross-section | 26,240 circular mils / 13.3 mm² |
Insulated outside diameter depends on the insulation type and manufacturer; check the cable spec sheet for conduit fill. Values computed on November 1, 2026 from this site's NEC 2023 tables.
6 AWG Wire FAQ
How many amps can 6 AWG wire carry?
6 AWG copper is rated 55/65/75 A at 60/75/90 °C and aluminum 40/50/55 A (NEC Table 310.16). With 75 °C terminals that is 65 A copper (60 A breaker) or 50 A aluminum (50 A breaker).
Can 6 AWG copper wire handle 60 amps?
A 6 AWG THHN/THWN-2 copper circuit in conduit with 75 °C terminals can be protected at 60 A, because the conductor is rated 65 A. If the load is continuous (3 hours or more), a 60 A circuit may carry only 48 A. 6 AWG NM-B (Romex) is limited to the 60 °C column, 55 A.
How many amps can 6 AWG wire carry at 240 volts?
The same as at 120 V: ampacity depends on the conductor and insulation, not the voltage. Voltage changes how far you can run it: a 50 A load stays within 3% drop up to about 146 ft at 240 V, but only 73 ft at 120 V (copper, resistance-only estimate).
Is 6 AWG wire good for a 50 amp circuit?
Yes. 6 AWG copper is rated at least 55 A in every 310.16 column, so it is the usual choice for a 50 A range, EV charger or sub-panel when the run is long or the cable is NM-B (8 AWG NM-B is only 40 A). A 50 A EV circuit supplies a charger set to 40 A continuous.
Common Uses for 6 AWG Wire
- 55–65A circuits — 50A spas, 60A sub-panels, large EV
- Detached garage and shop feeders
Calculate wire size for your load and distance
Use the calculator to size wire for your current, distance and voltage.