American Wire Gauge "AWG" Chart - Wire Size & Ampacity Table (2024)

AWG – American Wire Gauge Chart – Wire Size & Amps Rating Table

American Wire Gauge “AWG” is one of the important and standard tools in the US NEC (National Electrical Codes) used to sizing different cables and wires for multiple applications. Similarly to the SWG (Standard Wire Gauge) used in the UK, AWG is used to determine the ampacity of copper and aluminum wires for electrical wiring installations etc.

The AWG tables and charts are handy methods to specify the current carrying capacity of a conductor, its diameter, resistance, max current in amperes and other important parameters and characteristics.

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Table of Contents

AWG – American Wire Gauge

It is impossible to measure the exact amount of resistance in ohms of a wire having specific length for precise wire diameter. That’s where the AWG (American Wire Gauge) has played an important role since 1857.

The AWG is used to exactly measure the diameter of a particular conductor (such as solid, stranded, round and non-ferrous (alloys or metals that do not contain any appreciable amounts of iron) materials e.g. Aluminum, Copper etc). One of the most important roles of American Wire Gauge is to measure the current carrying capacity in Amps of wire (aka Wire Ampacity = The amount of maximum current that a conductor can carry continuously without exceeding its temperature rating.

One thing should be noted about the AWG that the larger the integer, the smaller the thickness and diameter of wire. For example, the 14AWG size is a suitable wire for a 15Amp circuit breaker, whereas the 8AWG size is most appropriate for 40Amps of circuit breakers and load points. In short, the ampacity is inversely proportional to the size of AWG integers (from 0000AWG to 40AWG) e.g. the higher the AWG size, the lower the ampacity and vise versa.

Good to know: The American Wire Gauge (AWG) is also known as B and S Gauge (Brown & Sharpe Gauge).

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The Wire Gauge (Measuring Tool)

If you are on the job site and need to know the wire size gauge for the particular load, one of the quick solutions is to use the handy device known as wire gauge tool. It is a small circular shaped disc where different but common numbers are printed on it in accordance with the specific slots and holes.

To use the wire gauge tool to find the suitable gauge size for a particular wire, simply remove the outer insulation and insert the wire conductor in the wire gauge slot one by one. If it is fixed properly in the slot (not hole), this is the exact gauge size (printed on that specific slot) of the wire.

Why are Wire Gauge Charts & Tables Important?

In any electrical installation system whether domestic or industrial, the selection of proper wire size and appropriate size of circuit breaker is very important. For example, if you need to install a water heater, what size of wire will you select? As you can’t use the same size of wire for all the electrical load points and higher wattage appliances. If so, the small wire for higher load may get hotter which leads to burn the wire as well as damage the circuit breaker and connected appliance to it. That’s where we need an AWG tool and related charts and tables to it.

Based on the wire size chart, you may select an “8 AWG” wire size and 50A of circuit breaker for 240V, 9000W, 240V water heater element wattage. We will show a solved example as well as the related AWG Wire size table for this in the following sections.

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Wire Gauge Chart & Table – AWG Gauge

The integers (as numbers) printed on the American Wire Gauge shows the gauge size. In AWG, there are a total of 44 gauges assigned to different numbers. In the list of standard sizes as integers, 4/0 (0000) is the largest diameter and 40AWG is the smallest diameter printed on AWG.

In addition, there are some special gauges such as 0000 (4/0), 000 (3/0), 00 (2/0) used for wire diameter and thickness larger than 0AWG. Instead of these complex stuff, wire gauge tables and charts are the alternative helpful resources based on the AWG. In these AWG gauge charts, most common gauge values show the different characteristics of wire such as its diameter, area, ampacity, resistance, current density, fusing current and temperature ratings etc.

The following AWG “American Wire Gauge” table shows the AWG Size and diameter in millimeter “mm” and inches in “in”, its cross sectional area in mm2, Inche2and kcmil or MCM andresistance in ohmsper 1000 feet and 1000 meter. The AWG size chart also shows thecurrent in amperes for chassis wiring and power transfer application.

AWG #DiameterCross Section AreaResistance in ΩCurrent in Amps
mminchmm2Inch2kcmilΩ / kftΩ / kmChassis WiringPower Transfer
0000 (4/0)11.68400.4600107.21930.1662211.60000.0490.1608380302
000 (3/0)10.40490.409685.02880.1318167.80640.06180.2028328239
00 (2/0)9.26580.364867.43090.1045133.07650.07790.2557283190
0 (1/0)8.25150.324953.47510.0829105.53450.09830.3224245150
17.34810.289342.40770.065783.69270.12390.4066211119
26.54370.257633.63080.052166.37130.15630.512718194
35.82730.229426.67050.041352.63480.1970.646415875
45.18940.204321.15060.032841.74130.24850.815213560
54.62130.181916.77320.026033.10240.31331.02811847
64.11540.162013.30180.020626.25140.39511.29610137
73.66490.144310.54880.016420.81830.49821.6348930
83.26360.12858.36560.013016.50970.62822.0617324
92.90640.11446.63420.010313.09270.79212.5996419
102.58820.10195.26120.008210.38300.99883.2775515
112.30480.09074.17230.00658.23411.264.1324712
122.05250.08083.30880.00516.52991.5885.211419.3
131.82780.07202.62400.00415.17852.0036.571357.4
141.62770.06412.08090.00324.10672.5258.285325.9
151.44950.05711.65020.00263.25683.18410.448284.7
161.29080.05081.30870.00202.58274.01513.174223.7
171.14950.04531.03780.00162.04825.06316.612192.9
181.02370.04030.82300.00131.62436.38520.948162.3
190.91160.03590.65270.00101.28818.05126.415141.8
200.81180.03200.51760.00081.021510.15233.308111.5
210.72290.02850.41050.00060.810112.80242.00191.2
220.64380.02530.32550.00050.642416.14352.96270.92
230.57330.02260.25820.00040.509520.35666.7844.70.729
240.51060.02010.20470.00030.404025.66884.2133.50.577
250.45470.01790.16240.00030.320432.367106.192.70.457
260.40490.01590.12880.000250.254140.814133.92.20.361
270.36060.01420.10210.000200.201551.466168.851.70.288
280.32110.01260.08100.000130.159864.897212.921.40.226
290.28590.01130.06420.000100.126781.833268.481.20.182
300.25460.01000.05090.000080.1005103.19338.550.860.142
310.22680.00890.04040.000060.0797130.12426.90.70.113
320.20190.00800.03200.000050.0632164.08538.320.530.091
330.17980.00710.02540.000040.0501206.9678.80.510.088
340.16010.00630.02010.0000310.0398260.9855.960.430.072
350.14260.00560.01600.0000250.0315328.981,079.30.430.072
360.12700.00500.01270.0000200.0250414.841,3610.330.056
370.11310.00450.01000.0000160.0198523.11,716.20.330.056
380.10070.00400.00800.0000120.0157659.622,164.10.270.044
390.08970.00350.00630.0000100.0125831.772,728.90.260.043
400.07990.00310.00500.0000080.00991,048.83,441.10.210.035

Note: Resistance of wires in Ω/km and Ω/kft are at 20°C or 68°F.

Here is the AWG wire size chart in image format if you need to download it for reference.

Click image to enlarge

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Calculation of Wire Diameter in mm & Inch, Cross Sectional Area in mm2, inch2 & kcmil & Resistance from it AWG Size

Wire Diameter in millimeters “mm“.

Dn= 27 × 10-3 × 92(36-n)÷39

or

DAWG = 8.251 × e-(0.1159) (AWG) … In millimeters (mm).

Where:

  • D = The wire diameter in millimeter “mm”.
  • n & AWG = Number of the gauge size.

Note: For larger gauge sizes like 4/0 (0000), 3/0 (000), 2/0 (00) & 0 (1/0), you may use the numbers for AWG as -3, -2, -1 and 0 respectively.

Wire Diameter in Inches “in”.

Dn = 5 × 10-3 × 92(36-n)÷39 In inches

Where:

  • D = The wire diameter in inches “in”.
  • n = Number of the gauge size.

Wire Cross Sectional Area in Square Millimeter “mm2“.

An = (π÷ 4) × Dn2

An = 12.668 ×10-3 V92(36-n)÷19.5

Where:

  • An= Cross sectional area of “n” gauge wire size in square millimeters “mm2“.
  • n = The number “#” of gauge size.
  • D = Wire square diameter in “mm2“.

Wire Cross Sectional Area inSquare Inches “in2“.

An=(π ÷ 4) ×Dn2

An= 19635 ×10-6 × 92(36-n)÷19.5

Where:

  • An = Cross sectional area of “n” gauge wire size in square inches “in2“.
  • n = The number “#” of gauge size.
  • D = Wire square diameter in “in2“.

Wire Cross Sectional Area in kcmil “kilo circular mils”.

An= 1000 ×Dn2 = 0.025 ×92(36-n)÷19.5

Where:

  • An = cross sectional area of “n” gauge wire size in kcmil.
  • kcmil = kilo circular mils.
  • n = the number of gauge size.
  • D = wire square diameter in in2.

Note: kcmil is also known as MCM “thousands of circular mils” i.e. 1kcmil = 1MCM = 0.5067 mm2.

  • 2MCM ≈ 1mm2
  • 1000 mils = 1 inch

In addition, MCM and kcmil is used for large diameter wires in AWG.

Resistance per 1000 feet at 20°C or 68°F:

Rn= 0.3048 × 109×ρ ÷(25.42xAn)

Where;

  • R = Resistance of the wire conductors in “Ω/kft”.
  • n = # of gauge size.
  • ρ = rho = resistivityin (Ω·m).
  • An = the cross sectional area of n #gauge in square inches “in2“.

Resistance per 1000 Meters at 20°C or 68°F:

Rn= 109 × ρ ÷An

Where

  • R = Resistance of the wire conductors “in Ω/km”.
  • n = # of gauge size.
  • ρ = rho = resistivity in (Ω·m).
  • An = the cross sectional area of n #gauge in square millimeters “mm2“.

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Wire Size Ampacity & Breaker Size Charts Based on AWG

Derived from the wire gauge chart and based on AWG sizes, the following fig shows the commonly used wire gauge size for different applications.

Click image to enlarge

The following AWG table shows the different AWG gauges and its associated ampacities and wire applications.

Wire GaugeRated AmpacityWire Applications
4/0 (0000)260 AmpsThe largest wire size likely to be found at residential electrical installations
3/0 (000)200 AmpsService entrance and feeder cable
1/0 (0)150 AmpsService entrance and feeder cable
2 Gauge95 AmpsLarge water heater elements
4 Gauge70 AmpsElectric furnaces, large electric heaters
6 Gauge55 AmpsFurnaces, cooktops and electric ranges
10 Gauge30 AmpsElectric clothes dryers, 240V window Air Conditioners, electric water heaters
12 Gauge20 AmpsKitchen, bathroom & outdoor receptacles (outlets) – 120V Air Conditioners
14 Gauge15 AmpsLight fixtures, lamps, receptacles, lighting circuits
16-Gauge13 AmpsExtension cords (light-duty)
18 Gauge10 AmpsLow-voltage lighting and lamp cords

You may downlead the above table as a reference sheet as follow:

Click image to enlarge

The following two charts shows the suitable circuit breaker sizes in Amps with wire gauge sizes and different level of voltages.

Click image to enlarge

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NEC Wire Size Table 310.15(B)(16) (Previously Table 310.16) & Chart based on AWG

NEC (National Electrical Code) Table 310.15(B)(16) (formerly Table 310.16) – 310.60 – ARTICLE 310 – Conductors for General Wiring & Allowable Ampacities of Conductors & Wire Sizes based on AWG (American Wire Gauge).

310.60 ARTICLE 310 — CONDUCTORS FOR GENERAL WIRING
Table 310.15(B)(16) (formerly Table 310.16) Allowable Ampacities of Insulated Conductors Rated Up to and Including 2000 Volts, 60°C Through 90°C (140°F Through 194°F), Not More Than Three Current-Carrying Conductors in Raceway, Cable, or Earth (Directly Buried), Based on Ambient Temperature of 30°C (86°F)*
Size AWG or kcmilTemperature Rating of Conductor [See Table 310.104(A).]Size AWG or kcmil
60°C (140°F)75°C (167°F)90°C (194°F)60°C (140°F)75°C (167°F)90°C (194°F)
Types TW, UFTypes RHW, THHW, THW, THWN, XHHW, USE, ZWTypes TBS, SA, SIS, FEP, FEPB, MI, RHH, RHW-2, THHN, THHW,

THW-2, THWN-2, USE-2, XHH, XHHW,

XHHW-2, ZW-2

Types TW, UFTypes RHW, THHW, THW, THWN, XHHW, USETypes TBS, SA, SIS, THHN, THHW,

THW-2, THWN-2, RHH, RHW-2, USE-2, XHH, XHHW, XHHW-2, ZW-2

COPPERALUMINUM OR COPPER-CLAD ALUMINUM
18**14
16**18
14**152025
12**20253015202512**
10**30354025303510**
84050553540458
65565754050556
47085955565754
3851001156575853
29511513075901002
1110130145851001151
1/01251501701001201351/0
2/01451751951151351502/0
3/01652002251301551753/0
4/01952302601501802054/0
250215255290170205230250
300240285320195230260300
350260310350210250280350
400280335380225270305400
500320380430260310350500
600350420475285340385600
700385460520315375425700
750400475535320385435750
800410490555330395445800
900435520585355425480900
10004555456153754455001000
12504955906654054855451250
15005256257054355205851500
17505456507354555456151750
20005556657504705606302000
  • *Refer to 310.15(B)(2) for the ampacity correction factors where the ambient temperature is other than 30°C (86°F). Refer to 310.15(B)(3)(a) for more than three current-carrying conductors.
  • **Refer to 240.4(D) for conductor overcurrent protection limitations.

Here is the NEC table as a chart (image format to downloads as a reference)

Click image to enlarge

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American Wire Gauge Ampacity Amperes AWG Breaker Size Cable Size Current Rating Table 310.15(B)(16) Table 310.16 Wire Size

American Wire Gauge "AWG" Chart - Wire Size & Ampacity Table (2024)

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