AWG Copper Wire Table

AWGDiam. (mils)Circular milsOhms/1000ftCurrent CarryingFusing CurrentFeet per Pound

00004602120000.050--1.56

0004101680000.063--1.96

003651330000.077--2.4826

0324.851055310.096--3.1305

1289.3836940.1264119.6-3.947

2257.6663580.159394.8-4.977

3229.4526240.200975.2-6.276

4204.3417380.253359.6-7.914

5181.9330880.391547.3-9.980

6162262440.402837.566812.58

7144.3208220.508029.756115.87

8128.5165120.640523.647220.01

9114.4130870.807718.739625.23

10101.9103841.01814.833331.82

1190.782261.28411.828040.12

1280.865291.6199.3323550.59

1372.051842.0427.4019763.80

1464.141092.5755.8716680.44

1557.132603.2474.65140101.4

1650.825814.0943.69117127.9

1745.320525.1632.9398.4161.3

1840.316246.5102.3282.9203.4

1935.912898.2101.8469.7256.5

2032.0102410.351.4658.4323.4

2128.581213.051.16-407.8

2225.364016.46.91841.2514.12

2322.651120.76.728-648.4

2420.140426.17.57729.2817.7

2517.932033.0.458-1031

2615.925341.62.36320.51300

2714.220252.48.288-1639

2812.615966.17.22814.42067

2911.312883.44.181-2607

3010.0100105.2.14410.23287

318.979132.7.114-4145

328.064167.3.090-5227

337.150.125211.0.072-6591

346.339.75266.0.0575.128310

355.631.5335.0454.2810480

365.025.0423.0363.6213210

374.4519.83533.028-16660

383.9715.7673.0222.521010

393.512.47848.018-26500

403.149.891070.0141.7733410

412.87.842--1.52-

422.4946.219--1.28-

432.2214.932--1.060-

441.9783.911--0.916-

451.7613.102----

461.5682.460----

471.3971.951----

481.2441.547----

491.1071.227----

500.9860.973----

Table of Bare Copper WireGeneral Notes:The wire size is different between the American Wire Gage [AWG] and the British standard. The table above only lists the AWG standard.AWG [American Wire Gauge] may also be called the Brown and Sharpe (B&S) Wire Gauge.The Birmingham Wire Gauge [BWG] is used for steel armor wire.Watch for round-off errors, as many numbers were rounded. Use the table as a guide.The weight [pound per foot] does not include wire insulation. The weight of the wire is critical in some applications.Circular mils is the diameter squared in mils.The editor has never seen the American Wire Gauge [AWG]

Current Notes:The current shown per wire size listed above is based on 1 amp/ 700 Circular mils, other tables provide different current per wire size, and different current for open air ~ check your local electrical code for the correct current capacity [Ampacity]. The 1 amp/ 700 Circular mils seems to be the most conservative, other sites provide/allow for 1 amp per 200 or 300 Circular mil. For shot wire lengths use 1A/200 Circular mil, for longer wire runs use 300 Circular mil, and for very long wire runs use the table above, 1 amp / 700 Circular mil.

The current rating is listed based on permissible voltage drop and not conductor heating.

The ability of a wire to carry a given amount of current is affected by a number of additional factors, which are not accounted for in the AWG table above. The ambient temperature of the surrounding air, wire insulation, and number of other wires bundled together [provided below].

Ampacity relates to the ability of the conductor to carry current [amps] before the cable over heats. There are hundreds of Ampacity tables for many different conditions. The numbers above are but one example. Ampacity Tables for many conditions:IEEE Standard 835, IEEE Standard Power Cable Ampacity TablesIEEE Standard 848, Procedure for the Determination of the Ampacity Derating of Fire Protected CablesICEA P-54-440, NEMA Pub. No. WC 51 - Ampacities of Cables in Open-Top Trays.

The National Electrical Code [NEC] requires their own cable sizing for premises wiring. Refer to the NEC rules to determine building wiring, as this page relates to electronic equipment wiring. For reference, the ampacity of copper wire at 300C for common wire sizes14 AWG may carry a maximum of 20 Amps in free air, or 15 Amps as part of a 3 conductor cable.12 AWG may carry a maximum of 25 Amps in free air, or 20 Amps as part of a 3 conductor cable.10 AWG may carry a maximum of 40 Amps in free air, or 30 Amps as part of a 3 conductor cable.8 AWG may carry a maximum of 70 Amps in free air, or 50 Amps as part of a 3 conductor cable.

The wire fusing [melting] current is based on the material the wire is made of, the diameter of the wire and the melting point of the the material. The wire fusing current of a wire is provided in tables as constant current or as [a larger] current for some given amount of time.This formula is used on a few different sites [un-verified]; I=Ad(3/2)@ d is in inches, A is a constant: A = 10,244 for Copper. A = 7,585 for Aluminum.I have listed a number of values for fusing current in the table above, for selected AWG sizes.

Aluminum wire properties are listed under on theAluminum electrical WirepageManufacturers listing forelectrical Wire and Cable{This Web Site}

Cable manufacturers will provide different numbers based on the insulation used for the wire.Use the table below to off-set the conservative current carrying numbers in the table above, and the fusing current. The table below lists copper wire with a Teflon [TFE] insulation. Teflon insulation has a higher operation temperature range then other insulators, for example PVC. The table below is based on data derived from MIL-STD-975, using 700C as the operating temperature. To derate based on number of wires in a bundle:IBW= ISWx (29 - #wire) / 28 @ [1 to 15 Bundled wires]IBW= ISWx (0.5) @ [more then 15 Bundled wires]ISW= Single wireIBW= Bundled wiresTo derate by temperature use; derate by 80% at 1500C, 70% at 1350C, or 50% at 1050C (per MIL-STD-975)Copper Wire TFE Insulated

AWGCurrent CarryingAWGCurrent Carrying

001690147

2108481

660844

10331225

14191613

189.2206.5

224.5243.3

262.5281.8

301.3--

DC Wire Table

Wire Loss Tables for Solar Electric SystemsIncludes 12, 24, and 120 volt charts and aMetric to AWG size conversion table.This isa five percenttable which means at these amperage ratings at the listed distances, 5% of the power would be lost to resistance. Five percent is normally acceptable in low voltage systems, butif you want a 2% figure, divide the given distances by 2.5. For a 10% loss multiply the distance by 2. For distances at 48 volts, double the 24 volt distances for a 5 percent loss figure. For 240 volt 5% loss, double the 120 volt distances. These distances include the NEC requirement for current over sizing of 25%.Example: For a pump drawing 9 amperes at 24 volts, located 88 feet from the battery bank: look at the center table for 24 volts. In the far left column find the next number higher than 9 (which is 10) and follow that line across the table until you find a distance figure greater than 88. At the top of the column find the gauge of wire (#8) that should be used. This method insures that wire losses are kept to an acceptable level without spending too much money on extra-heavy cable. Using a heavier wire than indicated, however, will result in even higher efficiencies and we do sometimes invest in the next larger gauge. Wire can get expensive, and it may not be worth the money to get that last 1% if you have to go to a much larger wire size.

Some of the newer grid tie systems inverters, such as the Sunny Boy, use up to 600 volts DC. Generally in these systems loss in wire is nothing to worry about. HOWEVER - you will have to be more careful about selecting and installing the wiring - high voltage DC is not something you want to do a 2nd rate wiring job on. Make sure the insulation is rated for 600 volts, and that there is no damage to the wire or insulation.We have also included a wire chart for convertingMetric to AWG(American Wire gauge) sizes.All distances are in FEETDo not use any wire sizes that might fall into the red zone - this would exceed the amperage rating of the wire and it may overheat and burn.

120 Volt AC or DC chartAmpsin WireWattsat 120V#14#12#10#8#6#4#21/02/03/0

2240422656

4480187328516

6720141225328562

8960103159272422666

10120084131216337534

1518005684131225356562

202400651031-8272422675

25300084131216337543

30360065.63112178281450722

40480084131216337543675

50600067103171272431543684

24 Volt DC chartAmpsin WireWattsat 24V#14#12#10#8#6#4#21/02/03/0

124169262412675

24884131207337532

4963766103169267

6144284566112178282

819221325484133216

1024017264367107169270

153601117264571112180289

204801321375484135217270343

2560017264367108172217274

307201322365690144180228

4096017264367108135171

5012001321345486108137

12 Volt DC chartAmpsin WireWattsat 12V#14#12#10#8#6#4#21/02/03/0

11284131206337532

2244266103168266432675

44818335284133216337543675

6721422335689141225360450570

8961016274266108168272338427

101208.51322335384135218270342

1518068.51322355690144180228

202406.61016274267108135171

2530081322335486108137

303606.6111828457290114

404808132133546785

These are one-way distances, measured from point A to point B. The out and back nature of electrical circuits has already been included. For PV arrays, figure the entire run, from the panels to the charge controller to the batteries

Cross referenceof AWG (American Wire Gauge) sizes to metric (mm)AWGmm2AWGmm2AWGmm2AWGmm2

300.05180.756164/0120

280.08171.0425300MCM150

260.14161.5235350MCM185

240.25142.5150500MCM240

220.34124.01/055600MCM300

210.38106.02/070750MCM400

200.508103/0951000MCM500

WIRE GAUGE TABLESAmerican Wire Gauge (AWG) sizes may be determined by measuring the diameter of the conductor (the bare wire) with the insulation removed. Refer to the Wire gauge Diameter Table for dimensions. When choosing wire gauge, the distance the wire must run and the amperage it will be expected to carry must be determined first. Refer to the Wire gauge Selection Table. Note that you can always use thicker wire (lower gauge number) than is recommended.METRIC-TO-AWG CONVERSION TABLE

Metric Sizemm2AWG Size

0.520

0.818

1.016

2.014

3.012

5.010

8.08

13.06

19.04

32.02

52.00

WIRE GAUGE DIAMETER TABLE

American Wire gaugeWire Diameter in inches

200.03196118

180.040303

160.0508214

140.064084

120.08080810

100.10189

80.128496

60.16202

50.18194

40.20431

30.22942

20.25763

10.2893

00.32486

000.3648

WIRE GAUGE SELECTION TABLE

Circuit AmperesCircuit WattsWire gauge (for length in feet)

6V12V6V12V3'5'7'10'15'20'25'

0 to 2.50 to 5153018181818181818

3.06183618181818181816

3.57214218181818181816

4.08244818181818181616

5.010306018181818161616

5.511336618181818161614

6.012367218181818161614

7.515459018181818141412

9.0185410818181616141412

10206012018181616141210

11226613218181616121210

12247214418181616121210

15309018018161614101010

20401202401816141210108

25501503001614121210108

5010030060012121010664

75150450900101088442

100200600120010886442

Find the amperes or watts the circuit is expected to carry on the left and the distance the wiring must run at the top - follow the columns until they intersect - for example, a 12 volt circuit which is 15 feet long and carries 10 amperes should use at least 16 gauge wire.

WIRE GAUGE AND CURRENT LIMITSAWG Wire Sizes (see table below)AWG: In the American Wire Gauge (AWG), diameters can be calculated by applying the formula D(AWG)=.00592((36-AWG)/39)inch. For the 00, 000, 0000 etc. gauges you use -1, -2, -3, which makes more sense mathematically than "double nought." This means that in American wire gage every 6 gauge decrease gives a doubling of the wire diameter, and every 3 gauge decrease doubles the wire cross sectional area. Similar to dB in signal and power levels. An approximate form of this formula contributed by Mario Rodriguez is D = .460 * (57/64)(awg +3)or D = .460 * (0.890625)(awg +3).

Metric Wire Gauges (see table below)Metric Gauge: In the Metric Gauge scale, the gauge is 10 times the diameter in millimeters, so a 50 gauge metric wire would be 5 mm in diameter. Note that in AWG the diameter goes up as the gauge goes down, but for metric gauges it is the opposite. Probably because of this confusion, most of the time metric sized wire is specified in millimeters rather than metric gauges.

Load Carrying Capacities (see table below)The following chart is a guideline of ampacity or copper wire current carrying capacity following theHandbook of Electronic Tables and Formulasfor American Wire Gauge. As you might guess, the rated ampacities are just a rule of thumb. In careful engineering the voltage drop, insulation temperature limit, thickness, thermal conductivity, and air convection and temperature should all be taken into account. The Maximum Amps for Power Transmission uses the 700 circular mils per amp rule, which is very very conservative. The Maximum Amps for Chassis Wiring is also a conservative rating, but is meant for wiring in air, and not in a bundle. For short lengths of wire, such as is used in battery packs you should trade off the resistance and load with size, weight, and flexibility. NOTE: For installations that need to conform to the National Electrical Code, you must use their guidelines. Contact your local electrician to find out what is legal!AWG gaugeConductorDiameter InchesConductorDiameter mmOhms per 1000 ft.Ohms per kmMaximum amps for chassis wiringMaximum amps forpower transmissionMaximum frequency for100% skin depth for solid conductor copper

OOOO0.4611.6840.0490.16072380302125 Hz

OOO0.409610.403840.06180.202704328239160 Hz

OO0.36489.265920.07790.255512283190200 Hz

00.32498.252460.09830.322424245150250 Hz

10.28937.348220.12390.406392211119325 Hz

20.25766.543040.15630.51266418194410 Hz

30.22945.826760.1970.6461615875500 Hz

40.20435.189220.24850.8150813560650 Hz

50.18194.620260.31331.02762411847810 Hz

60.1624.11480.39511.295928101371100 Hz

70.14433.665220.49821.63409689301300 Hz

80.12853.26390.62822.06049673241650 Hz

90.11442.905760.79212.59808864192050 Hz

100.10192.588260.99893.27639255152600 Hz

110.09072.303781.264.132847123200 Hz

120.08082.052321.5885.20864419.34150 Hz

130.0721.82882.0036.56984357.45300 Hz

140.06411.628142.5258.282325.96700 Hz

150.05711.450343.18410.44352284.78250 Hz

160.05081.290324.01613.17248223.711 k Hz

170.04531.150625.06416.60992192.913 k Hz

180.04031.023626.38520.9428162.317 kHz

190.03590.911868.05126.40728141.821 kHz

200.0320.812810.1533.292111.527 kHz

210.02850.723912.841.98491.233 kHz

220.02540.6451616.1452.939270.9242 kHz

230.02260.5740420.3666.78084.70.72953 kHz

240.02010.5105425.6784.19763.50.57768 kHz

250.01790.4546632.37106.17362.70.45785 kHz

260.01590.4038640.81133.85682.20.361107 kH

270.01420.3606851.47168.82161.70.288130 kHz

280.01260.3200464.9212.8721.40.226170 kHz

290.01130.2870281.83268.40241.20.182210 kHz

300.010.254103.2338.4960.860.142270 kHz

310.00890.22606130.1426.7280.70.113340 kHz

320.0080.2032164.1538.2480.530.091430 kHz

Metric 2.00.007870.200169.39555.610.510.088440 kHz

330.00710.18034206.9678.6320.430.072540 kHz

Metric 1.80.007090.180207.5680.550.430.072540 kHz

340.00630.16002260.9855.7520.330.056690 kHz

Metric 1.60.00630.16002260.9855.7520.330.056690 kHz

350.00560.142243291079.120.270.044870 kHz

Metric 1.4.00551.14033911140.260.043900 kHz

360.0050.127414.813600.210.0351100 kHz

Metric 1.25.004920.125428.214040.200.0341150 kHz

370.00450.1143523.117150.170.02891350 kHz

Metric 1.12.004410.112533.817500.1630.02771400 kHz

380.0040.1016659.621630.130.02281750 kHz

Metric 1.003940.1000670.221980.1260.02251750 kHz

390.00350.0889831.827280.110.01752250 kHz

400.00310.07874104934400.090.01372900 kHz

Voltage Drop Calculator by Gerald Newtonhttp://www.electrician2.com

The following calculator calculates the voltage drop, and voltage at the end of the wire for American Wire Gauge from 4/0 AWG to 30 AWG, aluminum or copper wire. (Note: It just calculates the voltage drop, consult the above table for rules-of-thumb, or your local or national electrical code or your electrician to decide what is legal!) Note that the voltage drop does not depend on the input voltage, just on the resistance of the wire and the load in amps.Top of FormSelect Copper or Aluminum Select American Wire Gauge (AWG) Size Select Voltage Enter 1-way circuitlength in feet (the calculation is for the round trip distance)

Enter Loadin amps

Voltage drop

Voltage at load end of circuit

Per Cent voltage drop

Wire cross section in circular mils

Bottom of Form

This chart of American Wire Gauge (AWG) wire sizes and rated ampacities is data intended for the pleasure of our readers only. Typographical errors, etc. are probable, since the typist is not a professional (our CEO). Please point out errors. The data listed are incomplete and should be used as a guideline only. Please contact manufacturers for the latest data.

Conductor sizeIt should be common-sense knowledge that liquids flow through large-diameter pipes easier than they do through small-diameter pipes (if you would like a practical illustration, try drinking a liquid through straws of different diameters). The same general principle holds for the flow of electrons through conductors: the broader the cross-sectional area (thickness) of the conductor, the more room for electrons to flow, and consequently, the easier it is for flow to occur (less resistance).Electricalwireis usually round in cross-section (although there are some unique exceptions to this rule), and comes in two basic varieties: solid and stranded. Solid copperwireis just as it sounds: a single, solid strand of copper the whole length of thewire. Strandedwireis composed of smaller strands of solid copperwiretwisted together to form a single, larger conductor. The greatest benefit of strandedwireis its mechanical flexibility, being able to withstand repeated bending and twisting much better than solid copper (which tends to fatigue and break after time).Wiresize can be measured in several ways. We could speak of awire's diameter, but since its really the cross-sectionalareathat matters most regarding the flow of electrons, we are better off designatingwiresize in terms of area.

Thewirecross-section picture shown above is, of course, not drawn to scale. The diameter is shown as being 0.1019 inches. Calculating the area of the cross-section with the formula Area = r2, we get an area of 0.008155 square inches:

These are fairly small numbers to work with, sowiresizes are often expressed in measures of thousandths-of-an-inch, ormils. For the illustrated example, we would say that the diameter of thewirewas 101.9 mils (0.1019 inch times 1000). We could also, if we wanted, express the area of thewirein the unit of square mils, calculating that value with the same circle-area formula, Area = r2:

However, electricians and others frequently concerned withwiresize use another unit of area measurement tailored specifically forwire's circular cross-section. This special unit is called thecircular mil(sometimes abbreviatedcmil). The sole purpose for having this special unit of measurement is to eliminate the need to invoke the factor (3.1415927 . . .) in the formula for calculating area, plus the need to figurewireradiuswhen you've been givendiameter. The formula for calculating the circular-mil area of a circularwireis very simple:

Because this is a unit ofareameasurement, the mathematical power of 2 is still in effect (doubling the width of a circle willalwaysquadruple its area, no matter what units are used, or if the width of that circle is expressed in terms of radius or diameter). To illustrate the difference between measurements in square mils and measurements in circular mils, I will compare a circle with a square, showing the area of each shape in both unit measures:

And for another size ofwire:

Obviously, the circle of a given diameter has less cross-sectional area than a square of width and height equal to the circle's diameter: both units of area measurement reflect that. However, it should be clear that the unit of "square mil" is really tailored for the convenient determination of a square's area, while "circular mil" is tailored for the convenient determination of a circle's area: the respective formula for each is simpler to work with. It must be understood that both units are valid for measuring the area of a shape, no matter what shape that may be. The conversion between circular mils and square mils is a simple ratio: there are (3.1415927 . . .) square mils to every 4 circular mils.Another measure of cross-sectionalwirearea is thegauge. The gauge scale is based on whole numbers rather than fractional or decimal inches. The larger the gauge number, the skinnier thewire; the smaller the gauge number, the fatter thewire. For those acquainted with shotguns, this inversely-proportional measurement scale should sound familiar.Thetableat the end of this section equates gauge with inch diameter, circular mils, and square inches for solidwire. The larger sizes ofwirereach an end of the common gauge scale (which naturally tops out at a value of 1), and are represented by a series of zeros. "3/0" is another way to represent "000," and is pronounced "triple-ought." Again, those acquainted with shotguns should recognize the terminology, strange as it may sound. To make matters even more confusing, there is more than one gauge "standard" in use around the world. For electrical conductorsizing, theAmericanWireGauge(AWG), also known as theBrown and Sharpe(B&S) gauge, is the measurement system of choice. In Canada and Great Britain, theBritish StandardWireGauge(SWG) is the legal measurement system for electrical conductors. Otherwiregauge systems exist in the world for classifyingwirediameter, such as theStubssteelwiregauge and theSteel MusicWireGauge(MWG), but these measurement systems apply to non-electricalwireuse.The AmericanWireGauge (AWG) measurement system, despite its oddities, was designed with a purpose: for every three steps in the gauge scale,wirearea (and weight per unit length) approximately doubles. This is a handy rule to remember when making roughwiresize estimations!Forverylargewiresizes (fatter than 4/0), thewiregauge system is typically abandoned for cross-sectional area measurement in thousands of circular mils (MCM), borrowing the old Roman numeral "M" to denote a multiple of "thousand" in front of "CM" for "circular mils." The followingtableofwiresizes does not show any sizes bigger than 4/0 gauge, becausesolidcopperwirebecomes impractical to handle at those sizes. Strandedwireconstruction is favored, instead.

WIRE TABLE FOR SOLID, ROUND COPPER CONDUCTORS

Size Diameter Cross-sectional area Weight AWG inches cir. mils sq. inches lb/1000 ft =============================================================== 4/0 -------- 0.4600 ------- 211,600 ------ 0.1662 ------ 640.5 3/0 -------- 0.4096 ------- 167,800 ------ 0.1318 ------ 507.9 2/0 -------- 0.3648 ------- 133,100 ------ 0.1045 ------ 402.8 1/0 -------- 0.3249 ------- 105,500 ----- 0.08289 ------ 319.5 1 -------- 0.2893 ------- 83,690 ------ 0.06573 ------ 253.5 2 -------- 0.2576 ------- 66,370 ------ 0.05213 ------ 200.9 3 -------- 0.2294 ------- 52,630 ------ 0.04134 ------ 159.3 4 -------- 0.2043 ------- 41,740 ------ 0.03278 ------ 126.4 5 -------- 0.1819 ------- 33,100 ------ 0.02600 ------ 100.2 6 -------- 0.1620 ------- 26,250 ------ 0.02062 ------ 79.46 7 -------- 0.1443 ------- 20,820 ------ 0.01635 ------ 63.02 8 -------- 0.1285 ------- 16,510 ------ 0.01297 ------ 49.97 9 -------- 0.1144 ------- 13,090 ------ 0.01028 ------ 39.63 10 -------- 0.1019 ------- 10,380 ------ 0.008155 ----- 31.43 11 -------- 0.09074 ------- 8,234 ------ 0.006467 ----- 24.92 12 -------- 0.08081 ------- 6,530 ------ 0.005129 ----- 19.77 13 -------- 0.07196 ------- 5,178 ------ 0.004067 ----- 15.68 14 -------- 0.06408 ------- 4,107 ------ 0.003225 ----- 12.43 15 -------- 0.05707 ------- 3,257 ------ 0.002558 ----- 9.858 16 -------- 0.05082 ------- 2,583 ------ 0.002028 ----- 7.818 17 -------- 0.04526 ------- 2,048 ------ 0.001609 ----- 6.200 18 -------- 0.04030 ------- 1,624 ------ 0.001276 ----- 4.917 19 -------- 0.03589 ------- 1,288 ------ 0.001012 ----- 3.899 20 -------- 0.03196 ------- 1,022 ----- 0.0008023 ----- 3.092 21 -------- 0.02846 ------- 810.1 ----- 0.0006363 ----- 2.452 22 -------- 0.02535 ------- 642.5 ----- 0.0005046 ----- 1.945 23 -------- 0.02257 ------- 509.5 ----- 0.0004001 ----- 1.542 24 -------- 0.02010 ------- 404.0 ----- 0.0003173 ----- 1.233 25 -------- 0.01790 ------- 320.4 ----- 0.0002517 ----- 0.9699 26 -------- 0.01594 ------- 254.1 ----- 0.0001996 ----- 0.7692 27 -------- 0.01420 ------- 201.5 ----- 0.0001583 ----- 0.6100 28 -------- 0.01264 ------- 159.8 ----- 0.0001255 ----- 0.4837 29 -------- 0.01126 ------- 126.7 ----- 0.00009954 ---- 0.3836 30 -------- 0.01003 ------- 100.5 ----- 0.00007894 ---- 0.3042 31 ------- 0.008928 ------- 79.70 ----- 0.00006260 ---- 0.2413 32 ------- 0.007950 ------- 63.21 ----- 0.00004964 ---- 0.1913 33 ------- 0.007080 ------- 50.13 ----- 0.00003937 ---- 0.1517 34 ------- 0.006305 ------- 39.75 ----- 0.00003122 ---- 0.1203 35 ------- 0.005615 ------- 31.52 ----- 0.00002476 0.09542 36 ------- 0.005000 ------- 25.00 ----- 0.00001963 0.07567 37 ------- 0.004453 ------- 19.83 ----- 0.00001557 0.06001 38 ------- 0.003965 ------- 15.72 ----- 0.00001235 0.04759 39 ------- 0.003531 ------- 12.47 ---- 0.000009793 0.03774 40 ------- 0.003145 ------- 9.888 ---- 0.000007766 0.02993 41 ------- 0.002800 ------- 7.842 ---- 0.000006159 0.02374 42 ------- 0.002494 ------- 6.219 ---- 0.000004884 0.01882 43 ------- 0.002221 ------- 4.932 ---- 0.000003873 0.01493 44 ------- 0.001978 ------- 3.911 ---- 0.000003072 0.01184

For some high-current applications, conductor sizes beyond the practical size limit of roundwireare required. In these instances, thick bars of solid metal calledbusbarsare used as conductors. Busbars are usually made of copper or aluminum, and are most often uninsulated. They are physically supported away from whatever framework or structure is holding them by insulator standoff mounts. Although a square or rectangular cross-section is very common for busbar shape, other shapes are used as well. Cross-sectional area for busbars is typically rated in terms of circular mils (even for square and rectangular bars!), most likely for the convenience of being able to directly equate busbar size with roundwire. REVIEW: Electrons flow through large-diameter wires easier than small-diameter wires, due to the greater cross-sectional area they have in which to move. Rather than measure smallwiresizes in inches, the unit of "mil" (1/1000 of an inch) is often employed. The cross-sectional area of awirecan be expressed in terms of square units (square inches or square mils), circular mils, or "gauge" scale. Calculating square-unitwirearea for a circularwireinvolves the circle area formula: Calculating circular-milwirearea for a circularwireis much simpler, due to the fact that the unit of "circular mil" was sized just for this purpose: to eliminate the "pi" and the d/2 (radius) factors in the formula. There are (3.1416) square mils for every 4 circular mils. Thegaugesystem ofwiresizingis based on whole numbers, larger numbers representing smaller-area wires and vice versa. Wires thicker than 1 gauge are represented by zeros: 0, 00, 000, and 0000 (spoken "single-ought," "double-ought," "triple-ought," and "quadruple-ought." Very largewiresizes are rated in thousands of circular mils (MCM's), typical for busbars andwiresizes beyond 4/0. Busbarsare solid bars of copper or aluminum used in high-current circuit construction. Connections made to busbars are usually welded or bolted, and the busbars are often bare (uninsulated), supported away from metal frames through the use of insulating standoffs.

Wire Size

Recently, there has been numerous questions on this board concerning the proper type or size of AC power cable to use with different amounts of equipment. It is very important to use the correct size cable to insure all the power will be available to your equipment and there is no danger of a fire or short from your cables.Here is a Cable/Current table to help you select the proper one to use in your application.Wire Size (AWG)2 Conductor3 Conductor4 Conductor

1030Amp2520

12252016

14181512

1613108

181076

Notice that the smaller the AWG number, the more current it can handle. All Extension Cords are required to list the wire gauge. That will tell you the amount of current they can safely handle.The wire in the above example is Copper type and of the same temperature rating. All currents listed are for Ambient temperature. Keep in mind that there are also many different type of insulation material that will determine the temperature rating. The wire may not be pure copper but an alloyed of aluminum, nickel, tin and copper.Standard cable, as used in home and general construction, is classified by the wire size, number of wires, insulation type and dampness condition of the wire environment.Example: a cable with the code "12/2 with Ground Type UF 600V (UL)" has the following specifications:1. Wire size is 12 gauge (minimum required size for homes today).

2. The "/2" indicates there are two wires in the cable.

3. "Ground" indicates there is a third wire in the cable to be used as a grounding wire.

4. "Type UF" indicates the insulation type and acceptable dampness rating.

5. "600V" means the wire is rated at 600 volts maximum.

6. "UL" indicates the wire has been certified by Underwriters Laboratory to be safe.

Standard wire color codes are very different between electronic circuitry and household 110 Volt AC wiring.

Household wiring (or other AC applications in the 100+ volt range) use the following color codes:BLACK"Hot" wire. Connected to Brass colored terminal.GREEEN"Ground" wire. Also called chassis ground.RED"Traveler" wire. Used for 3-ways switches.WHITE "Neutral" wire. Connected to silver colored terminal.VOLTAGE DROP vs. WIRE SIZEVoltage drop is the amount of voltage lost over the length of a circuit. Voltage drop changes as a function of the resistance of the wire and should be less than 2% if possible. If the drop is greater than 2%, efficiency of the equipment in the circuit is severely decreased and life of the equipment will be decreased. As an example, if the voltage drop on an incandescent light bulb is 10%, the light output of the bulb decreases over 30%!Voltage drop can be calculated using Ohmss Law, which is:Voltage Drop = Current in amperes x Resistance in ohms.For example, the voltage drop over a 200 foot long, #14 copper wire, power line supplying a 1000 watt floodlight is calculated as follows:Current = 1000watts/120volts = 8.33 amperes

Resistance of #14 copper wire = 2.58ohms/1000feet

Resistance of powerline=2 x 200ft x 0.00258ohms/ft=1.032ohms

Voltage drop = 8.33 amperes x 1.032 ohms = 8.60 volts

Percent voltage drop = 8.60volts/120volts = 7.2%

The 7.2% drop is over the maximum 2% so either the wattage of the bulb must be decreased or the diameter of the wire must be increased (a decrease in wire gauge number). If #9 copper wire were used in the above example, the voltage drop would have only been 2.2%.A more commonly used method of calculating voltage drop is as follows:K x 2 x Wire length in ft. x Current in amperes

Voltage Drop =-------------------------------------------------

Wire area in circular mils

K = Specific resistivity in ohm circular mils/footK = 11 for copper wire loaded at 50% of capacity.K = 12 for copper wire loaded to 50-100% capacity.K = 18 for aluminum wireUsing values from the Ohms Law example above: #14 copper wire has an area of 4110 circular mils, then voltage drop = (11 x 2 x 200 x 8.33) / 4110 = 8.92volts = 8.92volts/120volts = 7.4%.An interesting corollary to the above example is that if the line voltage doubles (240 volts instead of 120volts), the voltage drop decreased by a factor of 4. That means that a line can carry the same power 4 times further! Higher voltage lines are more efficient. Thats why voltage is so high (50,000volts) for power transmission lines.I hope this help explain many questions about AC power and cables.

WIRING TABLE NECAWG American Wire Gauge to mm2WIRING

Short TableAWGmm2AWGmm2AWGmm2AWGmm2

300.05180.756164/0120

280.08171.0425300MCM150

260.14161.5235350MCM185

240.25142.5150500MCM240

220.34124.01/055600MCM300

210.38106.02/070750MCM400

200.508103/0951000MCM500

AWG American Wire Gauge / Diameter / ResistanceUsed in the United States and other countries as a standard method of denoting wire diameter. The higher the number the thinner the wire. Thicker wire is generally capable of carrying larger amount of current over greater distances with less loss (though there are other things that cause current loss in wire). Sometimes the loss of cables is rated in Ohms per one thousand feet and for a particular type of wire the lower gauges (larger wires) have less resistance to current flow. (Sweetwater Archive)See:Maximum current load

AWG American Wire Gauge TableAWGDiameterDiameterSquareResistanceResistance

mminch mm2ohm/kmohm/1000 feet

460,040,001313700

440,050,00208750

420,060,00286070

410,070,00394460

400,080,00503420

390,090,00642700

380,100,00400,00782190

370,110,00450,00951810

360,130.0050,0131300445

350,140,00560,0151120

340,160.00630,020844280

330,180,00710,026676

AWGDiameterDiameterSquareResistanceResistance

mminch mm2ohm/kmohm/1000feet

320,200.0080,031547174

300,250.010,049351113

280,330.0130,08232.070.8

270,360.0180,09617854.4

260,410.0160,1313743.6

250,450,01790,16108

240,510.020,2087,527.3

220,640.0250,3351,716.8

200,810.0320,5034,110.5

181,020.040,8221,96.6

161,290.0511,313,04.2

141,630.0642,08,542.6

AWGDiameterDiameterSquareResistanceResistance

mminch mm2ohm/kmohm/1000feet

131,800,07202,66,76

122,050.0813,35.41.7

102.590.1025.263.41.0

83.250.1288..2962.20.67

64.1150.16513.2981.50.47

45.1890.204321.150.80.24

26.5430.257633.620.50.15

17.3480.289342.410.40.12

08.2520.32553.490.310.096

009.2660.36567.430.250.077

00010.400.409685.010.20.062

000011.6840.460107.2190.160.049

Metric GaugeMetric GaugeDiameterSquareResistance

mm mm2ohm/m

50,50,200,0838

60,60,280,0582

80,80,50,0328

101,00,80,0210

141,41,540,0107

161,62,00,00819

202,03,140,00524

252,54,910,00335

US National Electrical Codemaximum Amperage

AWG Wire SizeTwo Current Carrying ConductorsThree Current Carrying Conductors

AmpereAmpere

18710

161013

141518

122025

102530

83540

64555

46070

28095

Amperage for Power Extension Cords (US)(always uncoil the cord completely under oreration)

14 / 3 AWG Cable

LengthAmperage

50'15 A

100'13 A

150'8 A

200'6 A

250'5 A

300'4 A

12 / 3 AWG Cable

LengthAmperage

50'15 A

100'15 A

150'13 A

200'10 A

250'7 A

300'6 A

10 / 3 AWG Cable

LengthAmperage

50'15 A

100'15 A

150'15 A

200'15 A

250'13 A

300'10 A

AWG / Amperage and ConnectorsAWGmax. AmperageConnector

0000 (4/0)300 ACamLock

000 (3/0)260 ACamLock

00 (2/0)225 ACamLock

0 (1/0)195 ACamLock

2125 AC-Way (50')

490 AC-Way (50')

670 AJoy&Cabtire (25'&50')

850 AJoy&Cabtire (25'&50')

1030 AJoy&Cabtire (25'&50')

1220 AA.C. Wire (25'&50')

1415 AA.C. Wire (25'&50')

1610 AA.C. Wire

Amperage and Insulation HeatAmperage that is needed to heat up the insulation to a certain temperature (Copper Cable / different Insulation Materials) in free air (30C)

AWGPOLYPROPYLENE, POLYETHYLENE,(high density)at 90CPVC (irradiated), NYLONat 105CKAPTON, TEFLON, SILICONEat 200C

303 A3 A4 A

284 A4 A6 A

265 A5 A7 A

247 A7 A10 A

229 A10 A13 A

2012 A13 A17 A

1817 A18 A24 A

1622 A24 A32 A

1430 A33 A45 A

1240 A45 A55 A

1055 A58 A75 A

870 A75 A100 A

6100 A105 A135 A

4135 A145 A180 A

2180 A200 A240 A

Basic wire sizing guide for US 120 and 240 voltsUseful info:

# = American Wire Gauge (AWG), the lower the number the larger the wire guage."Service cable" is large insulated stranded copper cable (usually refers to single #4 wire and up).

Most house hold circuits (Typically 15 - 30 amp) can safely handle 95% to 100% of its max rating - but only for an hour or so at a time. Loads that require long periods of 'on' time (like an air conditioner, ballasts, etc) should not exceed 80% to 85% of the max rated load of the wire/cable. The known safe capacity that the National Electric Code (NEC) recommends at 100%, is actually 80% of load.

99.9% of the time when you get into "insulated" #8 and bigger wire, its most likely going to be stranded (just like its big sister "Service cable"). You can usually get your basic sheathed xx/2 and xx/3 cable up to 6 guage. If you need larger than #8 or #6 though, you will have to buy service or "service type" cable. This can cause two problems. One: very high cost on long runs. Two: the cable might not fit the appropriately-sized breaker on a long run. This is why its wise to opt for putting your ballast on 240V when 2400+ watts of light power is needed on a single circuit.

#4 and above = Cable1/0 and 2/0 are Service cable

120V (US) (@ 80% max load)(50ft run or less)GaugeAmpsWatts

#1691080

#14121440

#12161920

#10242880

#8323840

#6404800

#4485760

240V (US) (@ 80% max load)(50ft run or less)GaugeAmpsWatts

#1692160

#14122880

#12163840

#10245760

#8327680

#6409600

#44811520

Run LengthAmps100150150' - 200'200- 250'250'250' - 300'300300' - 400'400'400-500500'

12#12#10#8#6#4

16#10#8#6#4#2

24#8#6#4#2

32#6#4#2#1#1/0

40#6#4#2#1#1/0#2/0

Note:

For every extra 50 feet of cable/wire up to #8 normally you upgrade to the next size, consult you local codes if your unsure about double and triple length runs.

Ex: #6 is sometimes mandatory for a 200 foot 12 amp run but can be used up to 300 feet on a 12 amp circuit.

Note:Each time an additional plug is used in line of the run using 80% safe load, subtract an additional 2% from the over all power usage (80% to 78%).

Ex: One plug into the wall counts as your one 'free' plug.

WARNING: extension cords ARE included into the total length from breaker box (+25 feet and one gauge up), if intended for continuous use at said MAX safe power usage.

In addition, you need to make sure you getting what is actually equal to said gauge (if your making you own cord from something like SJO cable).

Recently, I have found that some places go by size and not current. A 12 gauge standard wire is actually the size of 10 gauge solid. This is to make up for it not being a solid connector. Bring something with you to compare wire size with what's printed/stamped on the sheeting. It should be one gauge bigger in size than what's on the sheeting.Ex: If you have a 1000W light and are using a 12 amp circuit, you should use a 15amp #12 extension cord no longer than 25 feet.

This info isnt complete and probably doesnt apply to many, cuz if your thinking this big you should already have a general understanding of codes and loads.

#4 (approx 65-75A each) used for 100-115 amp service#2 (approx 90A each) used for 125-150 amp service#1/0 (approx 150A each) used for 200 amp service#2/0 (approx 175A each) typically for industrial or vary long run with a large load. 300-350 amp service#0/3 (approx 200A each) typically for industrial or vary long run with a large load. 400 amp service

Service cable is specifically designed for extra service lines and or extra long (In structure or over-head) runs. 1/0 Gauge I believe is the only service cable (or cable) sold connected as x/3 (retail), provides a path fore both hots, the neutral and ground.Please specify wire / insulation /cable type. Tables fairly meaningless without.There is no accurate rule of thumb for distance / wire upsizing. I'm afraid one must do the math here, particularly with the price of wire what it is."Recently, I have found that some places go by size and not current. A 12 gauge standard wire is actually the size of 10 gauge solid. This is to make up for it not being a solid connector. Bring something with you to compare wire size with what's printed/stamped on the sheeting. It should be one gauge bigger in size than what's on the sheeting."Stranded wire is physically larger, but uses the same amount of copper. Carries the same amount of current. Solid wire dimension gauges are fairly worthless for measuring stranded wire.Stranded wire exhibits better electrical performance in AC circuits.

This page is to provide a single place to look to for what the safe rated capacities of various size wires in general use. These are general guidelines - check with the wire manufacturer or standards body controlling your installation for any additional specifications. Keep in mind that temperature and environment have a dramatic effect on these ratings, and that for wiring it's much better to err on the side of too large a wire than too small.This page started as a page for 12V DC automotive use, but has grown over time to include a more general set of information on wire sizing. I've tried to add some basic explanations of what matters when sizing a wire and to avoid using too many details specific to certain applications. The actual formulas used to figure this out can be very complex - for example the National Electrical Code specifies the wire sizes to be used in excruciating detail based on years of actual research on what happens to wires in The Real World. Keeping up with all those details can be very hard, but the basic principles are pretty straightforward. My goal for this page is to expose you to those basic concepts, and at the end to give a basic "rule of thumb" chart for folks to start out with.This page was created to help explain concepts and give an overview of wire capacity and what is factored into deciding on the wire size to use in a given application. This page shouldnotto be considered an authoritative source of exact numbers on what wire size to use. Consult other sources such as wiring codes and manufacturers recommendations on the piece of equipment you are installing for more details. I am not telling you what wire size to use - the information here is provided as-is and without any guarantee as to it's accuracy or completeness. Any issues caused by the use of this information are not my fault - be smart, use common sense, and use this information at your own risk.Measuring Wire CapacityThe amount of power a wire can safely carry is related to how hot it can safely get. All wires have resistance, and as power flows through a wire that resistance causes heat - and it can be quite a bit of heat. The more power you put through a wire, the hotter it gets. Insulation breaks down as it gets hot, and at some point it will melt away leaving the wire exposed to whatever is around it - other wires, grounded metal, people, etc. The heat can even be enough to start a fire in the surrounding material in some cases. Electrical fires are nasty and tend to start in the hardest to reach places - where the most heat builds up back in dark corners and tight spaces. This is why using the right size wires is important for your safety and for safety of others using your wiring work.In some respects, the capacity of a wire is actually best measured in watts, not amperage. Why? Because a watt is a unit or power that is a combination of amperage (volume), voltage (pressure), and resistance to the power flowing through that wire. Watts measure the amount of power (aka, heat) a wire can safely dissipate. However, most wire charts are done in amps. This is unfortunate because it means the wire chart is sort of assumed to be at a single voltage level. For most usage, this is fine because the chart has an assumed usage. As an example, charts for amperage ratings of of various sizes wires for 110V AC house current charts are popular and reasonably well-known. On the other hand, the amperage ratings are very different for common/typical 12V DC automotive usage. For example, a 12 gauge wire is commonly rated at 20A for 110V AC home usage, but in automotive 12V DC use 12 gauge wire is commonly used for circuits carrying 60A! A prime example would be the main charging wire from the alternator to the battery and out to the main electrical circuits of the car. I thought I had a satisfactory explanation posted here previously, but a few folks took aim at it and blew gaping holes in my understanding - without actually explaining what I was trying to understand or explain here. As of yet, I have not gotten a satisfactory explanation for this discrepancy. No one I've talked to as of yet has been able to explain it to me, but if you think you know the magic answer,please let me know. Maybe I'm missing something obvious. Maybe I'm just not understanding this as well I as think I am. Who knows... At any rate, the chart below reflects the difference in 110V AC vs. 12V DC usage, even though I'm still at a loss to explain the details.Remember, if in doubt, it's always better to put in too big of a wire than too small of a wire.Stranded vs. Solid WireThis one is a bit of a mind-boggler, but it's important. When electricity flows through a wire, it mostly flows on the surface of the wire, not through the middle. This effect is more pronounced on high frequency AC than it is on DC or low frequency AC. This means that a "wire" of a given size that made up of many smaller strands can carry more power than a solid wire - simply because the stranded wire has more surface area. This is one reason why battery cables in your car and welding cables are made up of many very fine strands of smaller wire - it allows them to safely carry more power with less of that power being dissipated as heat. However, this "skin" effect is not as pronounced in a typical 12V DC automotive application, and the wire and cable used there is stranded for flexibility reasons.When looking at a chart or description of wire capacity, take note of whether it is referring to stranded or solid wire - some charts may not specify but instead assume a default based on the typical wiring used in a given application. For example, almost all automotive wiring is stranded while almost all home wiring is solid. For most applications, flexibility or the lack thereof will be more important, but for very high frequency AC applications, stranded wire might be a requirement.Open Air vs. Bundles and/or ConduitsHeat is the primary determiner of the maximum amount of power any wire can carry, and the ability of that wire to dissipate that heat has a large impact on the final rating. Wires that are run in bundles (such as in a wiring harness or wiring conduit) cannot dissipate heat as easily as a single wire run in "open air", and as such must be "de-rated" to less than their maximum value to account for this. Also, wires that are run in areas that are unusually hot (such as in an attic or in an engine compartment) may need similar de-ratings. If both situations are encountered together (bundled wires in an unusually hot environment) then you need to de-rate forbothfactors and the capacity is further reduced.In a car, almost all wiring is run in a bundle, and much of it runs near the engine. In a house, a lot of wiring typically runs through the attic, often in a bundle/group and sometimes in a conduit. Pay attention to this and size your wires appropriately.Wire LengthSince all wires have resistance, the longer the wire, the greater the resistance. This means that for longer wiring runs you need to use a larger wire to compensate. This phenomenon is often referred to as "voltage drop", and for lower voltage automotive systems, the loss of 2V or even 1V can be significant. On longer wire runs, plan on using a larger size wire. There are specific voltage drop calculations that depend on the wire size in use, the length of the wire, the load applied, and the voltage in use. The National Electric Code has tons of charts for this, but there's anifty online voltage drop calculatorthat one of my readers pointed out to me that does 120V AC as well as 12V DC - and even 6V DC. You'd be surprised at some of the voltage drops you can find just form the wiring in use, so experiment with the calculator a bit to see if it's worth going to the next highest size wire in your application. On automotive applications of only 12V, losing a single volt of power in the wire is a whopping 8% loss, so it can be a big deal for voltage critical applications like your headlights where more voltage = more light. Kudos to Ron White for providing me with the link to thatcalculator, and kudos to the folks over atPowerStream.comfor putting that calculator and other data online.Duration of UsageSome electrical loads are continuous for long periods of times (like a light in your house or the headlights on your car) and some are much more intermittent (like a garbage disposal in your house or the starter in your car). This affects the wire size used - the longer a wire is in use, the more heat it will tend to retain. A wire for something that is only used for short periods (like the starter in your car) does not need quite as large of a wire as something that will be in use for very long periods of time. This means that for long-duration uses, you must de-rate the wire even further and use a larger size.Electrical CalculationsThere are four basic units of measurement for electricity: Power, measured in Watts, commonly referred to as "P" Current, measured in Amps, commonly referred to as "I" Voltage, measured in Volts, commonly referred to as "V" Resistance, measured in Ohms, commonly referred to as "R"There are a number of formulas that relate each of these four things - they all change in relationship to one another such that if you know any two you can calculate the other two. Lots of folks on the Internet have easy-to use calculators that allow you to do this online -http://www.sengpielaudio.com/calculator-ohm.htmis one. The formula wheel below was on their website and presents the info in a pretty easy to understand format.

Capacity ChartThis chart is a simple "max capacity" chart for a short wire run. Increase the wire size for long runs - for example the wires running to the back of a vehicle to power the taillights may need to be one size larger to account for the length.Gauge110V12V

225A5A

207.5A8A

1810A10A

1613A20A

1417A40A

1223A60A

1033A100A

846A150A

660A??A

480A??A

2100A??A

1125A??A

0150A??A

Chart Notes This 110V column in this chart was provided by one of my readers and according to him it is based on the data in The Howard W. Sams Engineering Staff fifth edition 1983 for stranded copper wire when used in a conduit or bundle. (Open air ratings would be higher, solid copper wire ratings might be slightly lower.) This data seems in line with commonly accepted usage for 120/220V home electrical wiring. The 12V column is based on various sources I have found across the Internet combined with the accepted usage in various vehicles I have worked on. I am generally a bit skeptical of the max capacity the sources I found claimed for some of the smaller wire sizes. For example, 16 gauge wire is mighty thin to run 20A through for even a short distance, and this chart is aconservativeinterpretation of the data I found out there. Some data had the max capacity even higher than this - yikes! The values here for 12V usage are not yet certified to be correct/valid/safe - they are my ballpark figures based on what I believe to be true based on what I have learned. Consult other sources of information for your specific application for more details.

Wire Type and Sizing Considerations

Written by Richard

Friday, 10 August 2007

Wire Type and Sizing ConsiderationsWhen a professional electrician looks at a job to wire a house or a new circuit in any structure the primary consideration in the wiring job is the size and type of wire to be used for job. The same for a plumber when looking at a job the plumber will size the pipes based on the number of gallons needed to carry the proper amount of water to its destination. If the pipe is too small then the water needed will not reach its destination. This is almost the same for electrical wire except under-sizing electrical wire is dangerous. Electrical wire carries voltage but it is the current rating of the power loads which is the primary factor in determining the size and type of wire to be used for the job. The current or amps, like the water pipe, is measured by how much flow there is in the wire. If the wire is too small and the flow too fast then wire gets hot. If it gets too hot then the insulation melts and a dangerous condition exists. If the wire runs for a prolonged period of time at a higher than rated temperature there are also corrosive effects at terminal connections. Eventually the corrosion and the excessive heat will cause the wire to become brittle. Solid wire will become brittle enough to eventually break off completely while stranded wire will lose strands one strand at a time from this effect. This causes the wire to become smaller and the heat increases. Eventually the current becomes too much for the wire and it breaks off again creating a dangerous condition. The equipment or device being supplied electricity from this wire, when it breaks, ceases to function while a live wire is hanging inside a control panel or other panel. This is why it is very important to properly size electrical wires for any type of electrical work and not to overload existing circuits in homes and businesses. Imagine a wire inside of a wall getting too hot and the insulation melting. This creates a dangerous electrical situation and also is a fire hazard.

Wire Type for the ApplicationOne other consideration in electrical wiring is choosing the right wire type. This usually refers to the insulation of the wire and its temperature rating. Selecting the approapiate insulation type and temperature rating is important and depnds on the environment and application of where the wire will be used. Romex is an all purpose wire almost used exclusively in residential wiring where the heat is not excessive and the wire is not subject to damage. Each specific type of wire has its own application and temperature rating and must be used in accordance with the NEC (National Electrical Code). Some wire is rated for direct burial underground while other wire is not rated for direct burial and must be used on conduit when run underground. Always refer to the NEC or your local electrical inspector for rules pertaining to the type of wire and the application. Wire Sizing ChartThe following chart shows the proper wire size or wire guage ( awg ) for the desired current or amperage.* The national electric code (NEC) specifies that the over-current protection device (breaker, fuse, or motor over-load) not exceed 15A for 14 AWG wire, 20A for 12 AGW wire, and 30A for 10 AGW wire.Maximum Ampacity for Copperand Aluminum Wire

Wire SizeCopperAluminum

167(75C)194(90C)167(75C)194(90C)

*1420 (*15)25.

*1225 (*20)302025

*1035 (*30)403035

850554045

665755060

485956575

211513090100

Wire Size and Amp Ratings

Wire Gauge SizeCopperAluminum

60C(140F)75C(167F)90C(194F)75C(167F)90C(194F)

NM-BTHWTHWN-2THWXHHW-2

UF-BTHWNTHHNTHWNTHHN

SEXHHW-2SETHWN-2

USEUSE-2USE

XHHWXHHW

14151515------

122020201515

103030302525

84050554045

65565755060

47085956575

3851001107585

29511513090100

1---130150100115

1/0---150170120135

2/0---175195135150

3/0---200225155175

4/0---230260180205

250---255290205230

300---285320230255

350---310350250280

500---380430310350

600---420475340385

750---475535385435

1000---545615445500

WARNING!Installation of electrical wire can be hazardous, if done improperly, can result in personal injury or property damage. For safe wiring practices, consult the National Electrical Code and your local building inspector.

American Wire Gauge Chart

AWGDIAMETERAREAWEIGHT(KILOGRAMS PER METER)TURNS OF WIRE(PER INCH)

0000 (4/0)0.46" (11.7mm)212 kcmil (107mm)0.9532.17

000 (3/0)0.41" (10.4mm)168 kcmil (85 mm)0.7562.44

00 (2/0)0.365" (9.27mm)133 kcmil (67.4 mm)0.5992.74

00.325" (8.25 mm)106 kcmil (53.5 mm)0.4753.08

10.289" (7.35 mm)83.7 kcmil (42.4 mm)0.3773.46

20.258" (6.54 mm)66.4 kcmil (33.6 mm)0.2993.88

30.229" (5.83 mm)52.6 kcmil (26.7 mm)0.2374.36

40.204" (5.19 mm)41.7 kcmil (21.2 mm)0.1884.89

50.182" (4.62 mm)33.1 kcmil (16.8 mm)0.1495.5

60.162" (4.12 mm)26.3 kcmil (13.3 mm)0.1186.17

70.144" (3.66 mm)20.8 kcmil (10.5 mm)0.09386.93

80.128" (3.26 mm)16.5 kcmil (8.37 mm)0.07447.78

90.114" (2.91 mm)13.1 kcmil (6.63 mm)0.0598.74

100.102" (2.59 mm)10.4 kcmil (5.26 mm)0.04689.81

110.0907" (2.30 mm)8.23 kcmil (4.17 mm)0.037111

120.0808" (2.05 mm)6.53 kcmil (3.31 mm)0.029412.4

130.0720" (1.83 mm)5.18 kcmil (2.62 mm)0.023413.9

140.0641" (1.63 mm)4.11 kcmil (2.08 mm)0.018515.6

150.0571" (1.45 mm)3.26 kcmil (1.65 mm)0.014717.5

160.0508" (1.29 mm)2.58 kcmil (1.31 mm)0.011619.7

170.0453" (1.15 mm)2.05 kcmil (1.04 mm)0.0092222.1

180.0403" (1.02 mm)1.62 kcmil (0.823 mm)0.0073224.8

190.0359" (0.912 mm)1.29 kcmil 0.653 mm)0.005827.9

200.032" (0.812 mm)1.02 kcmil 0.518 mm)0.004631.3

210.0285" (0.723 mm)0.810 kcmil (0.410 mm)0.0036535.1

220.0253" (0.644 mm)0.642 kcmil (0.326 mm)0.0028939.5

230.0226" (0.573 mm)0.509 kcmil (0.258 mm)0.0022944.3

240.0201" (0.511 mm)0.404 kcmil (0.205 mm)0.0018249.7

250.0179" (0.455 mm)0.320 kcmil (0.162 mm)0.0014455.9

260.0159" (0.405 mm)0.254 kcmil (0.129 mm)0.0011462.7

270.0142" (0.361 mm)0.202 kcmil (0.102 mm)0.00090870.4

280.0126" ( 0.321 mm)0.16 kcmil (0.081 mm)0.0007279.1

290.0113" (0.286 mm)0.127 kcmil (0.0642 mm)0.00057188.8

300.01" (0.255 mm)0.101 kcmil (0.0509 mm)0.00045399.7

310.00893" (0.227 mm)0.0797 kcmil (0.0404 mm)0.000359112

320.00795" (0.202 mm)0.0632 kcmil (0.032 mm)0.000285126

330.00708" (0.18 mm)0.0501 kcmil (0.0254 mm)0.000226141

340.00630" (0.16 mm)0.0398 kcmil (0.0201 mm)0.000179159

350.00561" (0.143 mm)0.0315 kcmil (0.0160 mm)0.000142178

360.005" (0.127mm)0.025 kcmil (0.0127 mm)0.000113200

370.00445" (0.113 mm)0.0198 kcmil (0.01 mm)0.0000893225

380.00397" (0.101 mm)0.0157 kcmil (0.00797 mm)0.0000708252

390.00353" (0.0897 mm)0.0125 kcmil (0.00632 mm)0.0000562283

400.00314" (0.0799 mm)0.00989 kcmil (0.00501 mm)0.0000445318

Which wire gauges am I most likely to encounter?Even though 44 different wire diameters are recognized within the AWG standard, theyre not all widely used, and most people are likely to encounter only a small range of them. Below are a few common cable types we use ever day, as well as the AWG sizes that correspond to them: Speaker Cable: 14 and 16 AWG Coaxial Cable(for cable TV and a few Ethernet applications): 18 and 20 AWG Cat 5, Cat 5e, and Cat 6 cables(for LANs and Ethernet): 24 AWG Telephone Cable: 22 28 AWG

For more great information on American Wire Gauge, including wire diameter formula, check outWikipedia's section on AWG.