14 AWG Wire — Ampacity, Conduit Fill & Dimensions

Everything the code tables say about 14 AWG conductors on one page: ampacity by temperature rating, breaker limits, conduit fill, physical size, resistance and voltage-drop distances.

14 AWG copper carries 15 A at 60°C, 20 A at 75°C and 25 A at 90°C. Overcurrent protection is capped at 15 A for copper by the small-conductor rule in 240.4(D), whatever the ampacity column says.

Copper, 75°C

20 A

Aluminum, 75°C

— A

Conductor area

4,110 cmil · 2.08 mm²

THHN diameter

0.111 in

DC resistance, Cu

3.14 Ω/1000 ft

14 AWG ampacity

14 AWG ampacity (amps), 30°C ambient, not more than three current-carrying conductors
	Copper			Aluminum
Installation	60°C	75°C	90°C	60°C	75°C	90°C
Raceway, cable or earth — Table 310.16	15	20	25	—	—	—
Single conductor in free air — Table 310.17	25	30	35	—	—	—

Typical use: 15 A lighting and general-purpose receptacle circuits.

Use the column that matches the lowest temperature rating in the circuit — usually the 75°C terminations on breakers and lugs. The 90°C column is a starting point for derating, not a rating you can load the wire to. NM-B (Romex) cable is always limited to the 60°C column.

As a copper equipment grounding conductor, 14 AWG is the minimum for circuits protected at up to 15 A. See the grounding conductor table.

14 AWG conduit fill

How many 14 AWG THHN wires fit in conduit (40% fill)
Conduit	1/2"	3/4"	1"	1-1/4"	1-1/2"	2"	2-1/2"	3"	4"
EMT	12	22	35	61	84	138	241	364	608
PVC Schedule 40	11	21	34	60	82	135	193	299	517
PVC Schedule 80	9	17	28	51	70	118	170	265	464
Rigid Metal Conduit	13	22	36	63	85	140	200	309	531
IMC	14	24	39	68	91	149	211	326	562
Flexible Metal Conduit	13	22	33	52	76	135	202	291	518
Liquidtight Flexible Metal Conduit	13	22	36	63	81	134	201	308	523
ENT	11	21	34	60	82	135	—	—	—

Mixing sizes or using another insulation? Use the conduit fill calculator.

14 AWG dimensions

14 AWG overall diameter and area including insulation
Insulation	Diameter (in)	Diameter (mm)	Area (in²)	Area (mm²)
THHN, THWN, THWN-2	0.111	2.82	0.0097	6.3
XHHW, XHHW-2, XHH	0.133	3.38	0.0139	9.0
TW, THW, THHW, THW-2	0.133	3.38	0.0139	9.0
RHH, RHW, RHW-2 (with outer covering)	0.193	4.90	0.0293	18.9

14 AWG voltage drop

Maximum one-way length of 14 AWG copper for 3% voltage drop
Load	120 V 1-phase	240 V 1-phase	208 V 3-phase	480 V 3-phase
5 A	114 ft	229 ft	229 ft	529 ft
10 A	57 ft	114 ft	114 ft	264 ft
15 A	38 ft	76 ft	76 ft	176 ft

Based on 3.14 Ω per 1000 ft for stranded copper at 75°C. For other loads and lengths use the voltage drop calculator.

All wire sizes

Frequently asked questions

How many amps can 14 AWG wire carry?

14 AWG copper is rated 15 A at 60°C, 20 A at 75°C and 25 A at 90°C when run in conduit or cable. Breaker size is limited to 15 A for copper.

What size conduit do I need for 14 AWG wire?

Three 14 AWG THHN conductors need at least 1/2-inch EMT. 1/2-inch EMT holds 12 and 3/4-inch holds 22.

What is the diameter of 14 AWG wire?

The bare conductor is 4,110 circular mils (2.08 mm²). With THHN insulation the overall diameter is about 0.111 in (2.82 mm) and the area is 0.0097 in², which is the figure used for conduit fill.

How far can I run 14 AWG wire?

For a 3% voltage drop on a 240 V single-phase circuit carrying 15 A, about 76 feet one way in copper. Halve that at 120 V. Lighter loads go proportionally farther.

NECTables.com is an independent reference and is not affiliated with, endorsed by, or a substitute for the National Fire Protection Association (NFPA). NEC® and National Electrical Code® are registered trademarks of the NFPA. Values shown are commonly published engineering data and independent calculations based on the methods of NFPA 70; they are not a reproduction of the Code. Always confirm against the edition adopted in your jurisdiction, including local amendments, and consult a licensed electrician or engineer before doing electrical work.