7/28/2019 Cables Wires and Conductors

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Cables Wires and ConductorsA wire is a single rod of metal with a small ratio of diameter to length.

A conductor is a wire suitable for carrying an electric current.

A stranded conductor is a conductor made up of a group of wires. These wires are usually twisted

together.

A cable is either a single stranded conductor or a combination of conductors insulated from oneanother (a mutlti-core cable). Cables in the oil and gas and petrochem industries are generally always

insulated and often protected with an armoured sheath. In general, stranded conductors are more

flexible and less susceptible to fatigue-failure than solid wires.

Cable SizingWires can carry only a limited amount of current safely. If the current flowing through a wire exceeds

the current-carrying capacity of the wire, excess heat is generated. This heat may be great enough to

burn off the insulation around the wire andstarta fire. An increase in the diameter, or cross section,

of a wire conductor decreases its resistance and increases its capacity to carry current.

Other reasons for choosing an increased cross sectionalareaof wire is to limit volt drop along its

length.

LimitationsWires and cables are made in standard diameters. When selecting cables it is common select thenext

standard size up from that calculated.

The terminals (e.g. Weidmuller, Phoenix etc) into which the cable or wire will terminate are made to

accomadate a range of sizes. Be aware of any limitations this may place on your selection.

DimensionsWire diameters are often specified in American Wire Gausge (AWG) rather than in mm or inches.

The charts below give dimensions of common diameters and the corresponding AWG.

Solid Bare Copper Wire

AWG Nominal

Diam

(mm)

Cross

Section

(mm2)

10 2.6 5.23

11 2.3 4.155

12 2.05 3.29

13 1.83 2.6314 1.63 2.07

15 1.45 1.651

16 1.29 1.3

17 1.15 1.039

18 1.02 0.816

19 0.912 0.653

20 0.813 0.514

21 0.724 0.41222 0.643 0.322

Stranded Tinned Copper Wire

AWG Stranding

No/AWG

Nominal

Diam

(mm)

Cross

Section

(mm2)

12 7/20 2.44 3.61

12 19/25 2.36 3.07

12 65/30 2.41 3.27

14 7/22 1.85 2.2614 19/26 1.85 1.93

14 42/30 1.85 2.06

16 7/24 1.52 1.42

16 19/29 1.47 1.216

16 65/34 1.5 1.3

18 7/26 1.22 0.891

18 19/30 1.24 0.957

18 42/34 1.2 0.81918 65/36 1.2 0.845

Spo

Fur

17t

E

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23 0.574 0.259

24 0.511 0.203

25 0.455 0.163

26 0.404 0.127

27 0.361 0.102

28 0.32 0.08

29 0.287 0.064

30 0.254 0.051

31 0.226 0.04

32 0.203 0.032

33 0.18 0.025

34 0.16 0.02

35 0.142 0.016

36 0.127 0.013

37 0.114 0.01

38 0.102 0.008

39 0.089 0.006

40 0.079 0.005

20 7/28 0.89 0.504

20 19/32 0.94 0.612

20 42/36 0.914 0.533

22 7/30 0.762 0.352

22 19/34 0.787 0.38

24 7/32 0.61 0.226

24 19/36 0.61 0.239

24 42/40 0.584 0.201

26 7/34 0.483 0.14

26 19/38 0.508 0.153

28 7/36 0.381 0.071

28 19/40 0.406 0.093

30 7/38 0.305 0.056