What is the limit on 14 gauge wire?
For reference, the National Electrical Code (NEC) notes the following ampacity for copper wire at 30 Celsius: 14 AWG - maximum of 20 Amps in free air, maximum of 15 Amps as part of a 3 conductor cable; 12 AWG - maximum of 25 Amps in free air, maximum of 20 Amps as part of a 3 conductor cable; 10 AWG - maximum of 40 ...
14-gauge is used for lamps, light fixtures, and lighting circuits with 15 amps. 16-gauge is best for extension cords supporting 13 amps. 12-gauge is ideal for use in the bathroom, kitchen, outdoor receptacles, and 120-volt AC's supporting 20 amps.
NO! You cannot use any 14 gauge wire on a 20 amp circuit. This is true, even running to a light fixture that has smaller wires built in. The wires built into the fixture are allowed as part of a manufactured assembly.
Doubling is allowed for much larger sizes. The #14 AWG Romex is not useless, keep it for any circuit that will be protected with 15A fuse. An exception is where the voltage drop is more than 5% ( extra long runs with high load), or exposed to high temperature.
When you are wiring a circuit that runs through more than one room, you have to use 14 gauge wire. This type of wire is thinner than 12 gauge and is not rated to handle the load from a 30 amp breaker.
14-gauge are usedfor light fixtures, lamps, lighting circuits with 15 amps. 12-gauge are used in kitchen, bathroom, outdoor receptacles, and 120-volt air conditioners supporting 20 amps. 10-gauge are used in electric clothes dryers, 240-volt window air conditioners, electric water heaters supporting 30 amps.
To determine what gauge wire you need, consider the carrying capacity and the amount of current the wire needs to conduct (measured in amperage or amps). Wire gauge is directly related to how many amps you need to run through it. The distance you need the wire to go can also impact the gauge of wire you need.
- Wire Diameter: 0.0641"
- Overall Diameter: 0.141"
- Insulation: PVC (0.030" Thick)
- Type: UL1015 Stranded Wire (41/30)
- Temperature Rating: 105°C (221°F)
A 20-amp circuit, protected by a 20-amp breaker or fuse, must be served by 12-gauge or 10-gauge wire.
What happens if you use a 14 gauge wire on a 20 amp circuit? 14 gauge wire is rated for 15 Amps. A 20Amp breaker/fuse would risk fire. The wire gets hot enough to melt the insulation and start fire.
Is it OK to use 14 2 wire for outlets?
14-gauge electrical wire, a.k.a. 14/2, can be used for outlets and lights on a 15-amp circuit. But it's most commonly used to power light fixtures that require low amperage. Most electrical outlets are on a 20-amp circuit which requires at least a 12-gauge wire.
A standard single-gang box has 18 cubic inches of space. That equates to enough room to hold 9 wires that are #14 gauge, 8 #12 gauge, or 7 #10 gauge.

Solid 14ga wire can be used to make rivets. Depending on the metal, this gauge may be difficult to bend. 14 gauge wire is often only available in dead soft temper. 12 gauge jewelry wire is fairly heavy.
Can I connect a 14 gauge wire to a 12 gauge wire? Of course you can. We do this sort of thing every single time we plug something into an outlet.
Is it safe to have a 14 gauge wire on a circuit protected by a 30 amp breaker? No, 14 gage wire uses a 15 amp breaker. A 30 amp breaker will allow twice the current a 14 gage wire can handle and can overheat the wire - fire hazard.
The NEC requires that dryers have a dedicated circuit with a minimum of 30 amps. 3 This calls for a 30-amp, double-pole breaker wired with 10 AWG wire.
For example, 14 AWG XHHW wire is rated for 30 amps, and 12 AWG XHHW wire is rated for 40 amps.
White 14-Gauge Solid THHN Cable is a single-conductor, copper electrical wire for indoor use. It has 15 allowable ampacities, is rated for 600-Volt and comes in 100 ft.
14 Gauge for 11-13 Amps. 12 Gauge for 14-15 Amps. 10 Gauge for 16-20 Amps.
For home wiring the following apply: #12 wire is rated for 1920 Watts at 120 volts. #14 wire is rated for 1440 Watts at 120 volts. These are rated at 80% load factors.