Size Matters

You'll probably accept noticed wires come in many different sizes.  Accept apart a relay and the coil has fine coper wire thinner than human hair.  On the other side are thick cables feeding power into homes and businesses.

With increasing size, wire can handle more electron menses (current, measured in Amperes).  Just similar a garden hose, a larger diameter hose carries more water in a given time over a given distance.

Wire sizes are most ofttimes measures in standardized American Wire Guage (AWG) sizes.  The electronics manufacture uses the diameter of the wire in predefined sizes for manufacturability and known electric characteristics.

components_ruler.jpg

The Adafruit Ruler has a handy wire approximate finder built in from eight to 28 AWG

Below is a tabular array of American Wire Gauge standard sizes and the characteristics of each wire size.  For a detail gauge, it has a set bore and cantankerous-sectional area.  When winding wire effectually for an inductor, coil, or transformer information technology is handy to know how thick the wire will stack upwards, which increases by wire gauge.  An of import measure is the electrical resistance of the wire which increases as the guess goes higher and the diameter decreases.  This is measured on ohms per kilometer or milliohms per meter.  Finally the last column for Americans lists national electrical code current capacity for larger gauge wires - it is a good demonstration of current chapters changing as wire expanse changes.

AWG Diameter Turns of Wire, no insul. Area Copper resistance Maximum Amperage
(mm) (per cm) (mm2) (Ω/km) for wiring
(mΩ/m) (amps)
0 (1/0) 8.251 ane.21 53.5 0.3224 245
1 7.348 1.36 42.four 0.4066 211
2 6.544 ane.53 33.6 0.5127 181
3 five.827 1.72 26.7 0.6465 158
iv 5.189 1.93 21.2 0.8152 135
5 4.621 ii.16 xvi.8 one.028  118
half-dozen four.115 2.43 13.three 1.296 101
7 3.665 2.73 10.five 1.634  89
viii 3.264 3.06 8.37 2.061 73
9 ii.906 3.44 6.63 2.599 64
10 2.588 3.86 5.26 three.277 55
11 2.305 4.34 4.17 4.132 47
12 2.053 4.87 3.31 v.211 41
xiii one.828 v.47 ii.62 6.571 35
14 1.628 6.14 two.08 8.286 32
fifteen 1.45 half-dozen.9 1.65 10.45 28
16 one.291 seven.75 1.31 13.17 22
17 i.15 eight.7 1.04 16.61 nineteen
xviii 1.024 nine.77 0.823 twenty.95 xvi
19 0.912 eleven 0.653 26.42 fourteen
20 0.812 12.3 0.518 33.31 11
21 0.723 thirteen.8 0.41 42.0 9
22 0.644 15.5 0.326 52.96 7, Common for breadboards
23 0.573 17.4 0.258 66.79 4.7
24 0.511 19.half dozen 0.205 84.22 three.five
25 0.455 22 0.162 106.2 2.7
26 0.405 24.7 0.129 133.9 2.2
27 0.361 27.7 0.102 168.nine 1.7
28 0.321 31.1 0.081 212.9 1.4
29 0.286 35 0.0642 268.v one.2
30 0.255 39.3 0.0509 338.6 0.86
31 0.227 44.i 0.0404 426.9 0.70
32 0.202 49.5 0.032 538.3 0.53
33 0.18 55.six 0.0254 678.8 0.43
34 0.16 62.4 0.0201 856 0.33
35 0.143 seventy.1 0.016 1079 0.27
36 0.127 78.vii 0.0127 1361 0.21
37 0.113 88.4 0.0100 1716 0.17
38 0.101 99.3 0.00797 2164 0.thirteen
39 0.0897 111 0.00632 2729 0.11
40 0.0799 125 0.00501 3441 0.09

Information technology is common to see the even size gauges in sizes 10 AWG and above.  The smaller odd sizes are non seen as often.

For a majority of projects, getting the exact gauge of wire is not a disquisitional factor - close plenty is usually fine. Here are some things to consider for choosing a gauge:

  1. Power - if yous accept high current requirements in a curcuit like large motors or many LED lights, select thicker wire starting at eighteen AWG and lower.  The size is based on handling the electric current while remaining absurd plus providing lower resistance.  This goes for wearables also - exercise not sew too many power hungry LEDs with the thinnest wire that cannot handle the current draw.
  2. Breadboards - typically breadboard holes only handle a modest range of wire gauges.  Too small a wire and it falls out or makes a poor connection.  Too large a wire will curve out a hole or simply not fit.  It is best to buy some wire specifically marketed for breadboards, nearly ofttimes 22 gauge.  Alternatively, if y'all run accross some solid phone wire from a contempo installation, it'southward a tad smaller but works.
  3. Resistance - Although much of the fourth dimension you lot can blueprint circuits thinking that wires accept near zero electrical resistance to current flow, there are times where you must choose wire and then that resistance is non a big factor. If temperature is a gene in resistance measurements, take the resistance per kilometer higher up (we'll characterization that R0), and for copper wire, resistance related to temperature is R = R0 * (1 + 0.004 * (T - twenty)) where the temperature T is in Celcius.  You tin can take resistance R and multiply by the number of kilometers for ohms, meters for milliohms.

This guide was start published on Jan 24, 2015. It was final updated on Jan 24, 2015.

This page (Wire Gauges) was last updated on Jun 08, 2022.

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