Notes

Standard Cable & Wire Sizes 

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IEC 60228 is the International Electrotechnical Commission's international standard on conductors of insulated cables.   Among other things, it defines a set of standard wire cross-sections:

International standard wire sizes (IEC 60228)
0.5 mm² 0.75 mm² 1 mm² 1.5 mm² 2.5 mm² 4 mm²
6 mm² 10 mm² 16 mm² 25 mm² 35 mm² 50 mm²
70 mm² 95 mm² 120 mm² 150 mm² 185 mm² 240 mm²
300 mm² 400 mm² 500 mm² 630 mm² 800 mm² 1000 mm²

 

In the United States, wire sizes are commonly measured in American Wire Gauge (AW). Increasing AWG give decreasing cross sectional areas (the smallest AWG size being 50 and the largest 0000). 

Metric AWG Conversion

Number strands/diameter
per strand 		Approximate overall
diameter
mm² Awg Circ.Mils inch mm inch mm
0.5 987 1/.032 1/.813 0.032 0.81
20 1020 7/.0121 7/.307 0.036 0.91
0.75 1480 1/.039 1/.991 0.039 0.99
18 1620 1/.0403 1/1.02 0.04 1.02
18 1620 7/.0152 7/.386 0.046 1.16
1 1974 1/.045 1/1.14 0.045 1.14
1 1974 7/.017 7/.432 0.051 1.3
16 2580 1/.0508 1/1.29 0.051 1.29
16 2580 7/.0192 7/.488 0.058 1.46
1.5 2960 1/.055 1/1.40 0.055 1.4
1.5 2960 7/.021 7/.533 0.063 1.6
14 4110 1/.0641 1/1.63 0.064 1.63
14 4110 7/.0242 7/.615 0.073 1.84
2.5 4934 1/.071 1/1.80 0.071 1.8
2.5 4934 7/.027 7/.686 0.081 2.06
12 6530 1/.0808 1/2.05 0.081 2.05
12 6530 7/.0305 7/.775 0.092 2.32
4 7894 1/.089 1/2.26 0.089 2.26
4 7894 7/.034 7/.864 0.102 2.59
10 10380 1/.1019 1/2.59 0.102 2.59
10 10380 7/.0385 7/.978 0.116 2.93
6 11840 1/.109 1/2.77 0.109 2.77
6 11840 7/.042 7/1.07 0.126 3.21
9 13090 1/.1144 1/2.91 0.1144 2.91
9 13090 7/.0432 7/1.10 0.13 3.3
8 16510 1/.1285 1/3.26 0.128 3.26
8 16510 7/.0486 7/1.23 0.146 3.7
10 19740 1/.141 1/3.58 0.141 3.58
10 19740 7/.054 7/1.37 0.162 4.12
7 20820 1/.1443 1/3.67 0.144 3.67
7 20820 7/.0545 7/1.38 0.164 4.15
6 26240 1/.162 1/4.11 0.162 4.11
6 26240 7/.0612 7/1.55 0.184 4.66
16 31580 7/.068 7/1.73 0.204 5.18
5 33090 7/.0688 7/1.75 0.206 5.24
4 41740 7/.0772 7/1.96 0.232 5.88
25 49340 7/.085 7/2.16 0.255 6.48
25 49340 19/.052 19/1.32 0.26 6.6
3 52620 7/.0867 7/2.20 0.26 6.61
2 66360 7/.0974 7/2.47 0.292 7.42
35 69070 7/.100 7/2.54 0.3 7.62
35 69070 19/.061 19/1.55 0.305 7.75
1 83690 19/.0664 19/1.69 0.332 9.43
50 98680 19/.073 19/1.85 0.365 9.27
1/0 105600 19/.0745 19/1.89 0.373 9.46
2/0 133100 19/.0837 19/2.13 0.419 10.6
70 138100 19/.086 19/2.18 0.43 10.9
3/0 167800 19/.094 19/2.39 0.47 11.9
3/0 167800 37/.0673 37/1.71 0.471 12
95 187500 19/.101 19/2.57 0.505 12.8
95 187500 37/.072 37/1.83 0.504 12.8
4/0 211600 19/.1055 19/2.68 0.528 13.4
120 237.8mcm 37/.081 37/2.06 0.567 14.4
250mcm 37/.0822 37/2.09 0.575 14.6
150 300mcm 37/.090 37/2.29 0.63 16
350mcm 37/.0973 37/2.47 0.681 17.3
185 365.1mcm 37/.100 37/2.54 0.7 17.8
400mcm 37/.104 37/2.64 0.728 18.5
240 473.6mcm 37/.114 37/2.90 0.798 20.3
240 473.6mcm 61/.089 61/2.26 0.801 20.3
500mcm 37/.1162 37/2.95 0.813 20.7
500mcm 61/.0905 61/2.30 0.814 20.7
300 592.1mcm 61/.099 61/2.51 0.891 22.6
600mcm 61/.0992 61/2.52 0.893 22.7
700mcm 61/.1071 61/2.72 0.964 24.5
750mcm 61/.1109 61/2.82 0.998 25.4
750mcm 91/.0908 91/2.31 0.999 25.4
400 789.4mcm 61/.114 61/2.90 1.026 26.1
800mcm 61/.1145 61/2.91 1.031 26.2
800mcm 61/.0938 91/2.38 1.032 26.2
500 1000mcm 61/.1280 61/3.25 1.152 29.3
1000mcm 91/.1048 91/2.66 1.153 29.3
625 1233.7mcm 91/.117 91/2.97 1.287 32.7
1250mcm 91/.1172 91/2.98 1.289 32.7
1250mcm 127/.0992 127/2.52 1.29 32.8
1500mcm 91/.1284 91/3.26 1.412 35.9
1500mcm 127/.1087 127/2.76 1.413 35.9
800 1578.8mcm 91/.132 91/3.35 1.452 36.9
1000 1973.5mcm 91/.147 91/3.73 1.617 41.1
2000mcm 127/.1255 127/3.19 1.632 41.5
2000mcm 169/.1088 169/2.76 1.632 41.5

Definitions

  • Circ.Mils - cross sectional area in Circular Mils
  • Awg  - American Wire Gauge size
  • mm² - Metric Wire Size mm²

See Also

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Steven McFadyen's avatar Steven McFadyen

Steven has over twenty five years experience working on some of the largest construction projects. He has a deep technical understanding of electrical engineering and is keen to share this knowledge. About the author

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View 3 Comments (old system)

  1. dara's avatar dara says:
    5/14/2012 7:13 AM

    I have examined some current capacity tables.The above rule of thumb did not work with me, particularly with sizes bellow 185 sq.mm

    • Steven's avatar Steven says:
      5/14/2012 7:16 AM

      Dara,

      Thanks for pointing this out. Your right the rule of thumb does not work well for cable capacities. It is always better to work these out properly. I’ve edited the article to remove the rule of thumb text.

  2. Notes's avatar Notes says:
    2/1/2013 10:30 AM

    Trackback from Notes

    IEC 60287 "Calculation of the continuous current rating of cables (100% load factor)" is the International Standard which defines the procedures and equations to be used in determining the current carry capacity of cable. The standard is applicable... ...

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