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American Wire Gauge Conductor Size Table

American wire gauge (AWG) is a standardized wire gauge system for the diameters of round, solid, nonferrous, electrically conducting wire. The larger the AWG number or wire guage, the smaller the physical size of the wire. The smallest AWG size is 40 and the largest is 0000 (4/0). AWG general rules of thumb – for every 6 gauge decrease, the wire diameter doubles and for every 3 gauge decrease, the cross sectional area doubles. Note – W&M Wire Gauge, US Steel Wire Gauge and Music Wire Gauge are different systems.

American Wire Gauge (AWG) Sizes and Properties Chart / Table

Table 1 lists the AWG sizes for electrical cables / conductors. In addition to wire size, the table provides values load (current) carrying capacity, resistance and skin effects. The resistances and skin depth noted are for copper conductors. A detailed description of each conductor property is described below Table 1.

AWG Notes: American Wire Gauge (AWG) is a standardized wire gauge system used predominantly in the United States to note the diameter of electrically conducting wire. The general rule of thumb is for every 6 gauge decrease the wire diameter doubles and every 3 gauge decrease doubles the cross sectional area.

Diameter Notes: A mil is a unit of length equal to 0.001 inch (a “milli-inch” or a “thousandth of one inch”) ie. 1 mil = 0.001″.

Resistance Notes: The resistance noted in the table above is for copper wire conductor. For a given current, you can use the noted resistance and apply Ohms Law to calculate the voltage drop across the conductor.

Current (ampacity) Notes: The current ratings shown in the table are for power transmission and have been determined using the rule of 1 amp per 700 circular mils, which is a very conservative rating. 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 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.

Skin Effect and Skin Depth Notes: Skin effect is the tendency of an alternating electric current (AC) to distribute itself within a conductor so that the current density near the surface of the conductor is greater than that at its core. That is, the electric current tends to flow at the “skin” of the conductor. The skin effect causes the effective resistance of the conductor to increase with the frequency of the current. The maximum frequency show is for 100% skin depth (ie. no skin effects)