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The number and type of electrical devices connected to a circuit determine the ampacity requirement of the conductor. Usually, a general-purpose house circuit is designed for 20 amps. Lighting circuits may be designed for only 15 amps.
Generally, a 20-amp circuit requires a wire gauge of at least 12 AWG (American Wire Gauge) for copper wire, or 10 AWG for aluminum wire, to ensure that the wire can handle the load without overheating or causing a fire hazard.
The closest sizes provided by the UL standards are for the selection of insulation and jacket thickness requirements. The National Electrical Code (NEC®), Canadian Electrical Code (CEC), and NOM-001-SEDE in Mexico do not provide ampacity values for metric conductor sizes.
Wire Size Chart. Electrical current is measured in amps. Each wire size, or wire gauge (AWG), has a maximum current limit that a wire can handle before damage occurs. It is important to pick the correct size of wire so that the wire doesn't overheat.
26 gru 2023 · Mostly 20-amp circuits are connected with 12-gauge or 10-gauge wire. With that, a 14-gauge wire is also connected that can carry 15-amp current. For a 20-amp circuit, it is suggested to use a 12-gauge wire. Use of a 14-gauge wire at 20 amps will cause overload, overheating, and fire.
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 Amps in free air, maximum of 30 Amps as part of a 3 conductor cable. Check your local electrical code for the correct current capacity (ampacity) for mains and in wall wiring.
Ampacity is the maximum current that a conductor can carry continuously under the conditions of use without exceeding its temperature rating. Cerrowire's ampacity chart helps calculate the load requirement for a circuit.
