Navigation Voltage Drop and Wire Gauge

Resistance and Voltage Drop Calculator


On a cable with two wires i.e. (+) and (-) the voltage drop takes place on both wires. This has been accounted for in the results!

U = R x I

Legend:
    U = Potential difference between two points on the wire
    I = Line current
    R = Measured resistance between the two points of potential difference





The following table shows the values using the AWG 'American Wire Gauge':

AWG Standard Copper Line : Resistance and Voltage Drop
Size Diameter Resistance @ 77F Resistance/Wire
length
(Ohm)
Voltage drop
2 Wire
(Volt)
AWG Metric
mm2
Circular
mils
inch mm ohm/1000' ohm/km
20 0.518 1.022 0.0369 0.938 10.3632 34.000
18 0.823 1.624 0.0465 1.182 6.5227 21.400
16 1.309 2.583 0.0587 1.491 4.0843 13.400
14 2.081 4.107 0.0740 1.880 2.5756 8.450
12 3.309 6.530 0.0933 2.371 1.6215 5.320
10 5.261 10.383 0.1177 2.989 1.0180 3.340
8 8.366 16.510 0.1484 3.770 0.6401 2.100
6 13.302 26.251 0.1871 4.753 0.4023 1.320
4 21.151 41.741 0.2360 5.994 0.2533 0.831
2 33.631 66.371 0.2976 7.558 0.1594 0.523
1 42.408 83.693 0.3341 8.487 0.1265 0.415
0 53.475 105.535 0.3752 9.530 0.1003 0.329
Enter:
Length in feet or Meters      Current in Ampere        


This table shows the values in metric diameters:

Standard Copper Line : Risistance and Voltage Drop
Size Diameter Resistance @ 77F Resistance/Wire
Length
(Ohm)
Voltage Drop
2 Wires
(Volt)
Nahe
AWG
Metric
mm2
Circular
mils
inch mm ohm/1000' ohm/km
21 0.50 0.986 0.0363 0.922 10.7290 35.200
18 0.85 1.677 0.0473 1.202 6.3094 20.700
17 1.25 2.467 0.0574 1.457 4.2977 14.100
15 2 3.947 0.0726 1.843 2.6792 8.790
13 3 5.921 0.0889 2.257 1.7861 5.860
11 5 9.868 0.1147 2.523 1.0729 3.520
9 8 15.788 0.1451 3.686 0.6706 2.200
5 20 39.471 0.2294 5.828 0.2679 0.879
Enter:
Length in feet or Meters      Current in Ampere         


The calculations carried out on this page are only theoretical values and need to be checked on sight and corrected if necessary.