Electrical Systems

General

The gauge of a wire is its size. The American Wire Gauge is a nationally accepted convention for designating wire sizes. The higher the number, the smaller the diameter of the wire. For example, 16 gauge wire has a smaller diameter than 12 gauge wire. For large sizes of wire, 0, 00, 000 and 0000 are used. The more zeros, the larger the wire.

FIGURE 2 - Conductor Gauge (insulation not included)

Conductors may be labeled with their size. If not, and the size is to be determined, then measure the diameter of an individual strand using a micrometer. Square the diameter of the strand (in mils) and multiply by the number of strands in the conductor. This will provide the total circular-mil area of the conductor. Refer to Table 1 to find the gauge.

TABLE 1 - Conductors

Formula:

CM=d2 x N

Where:

d = diameter of one strand in mils (one mil = .001 inch)

N = number of strands in the conductor

NOTE:

1. If the conductor contains strands of various sizes, measure the diameter of each strand, square the diameter, and add the individual circular mil area for the conductor.
2. Below 50 volts, SAE wire size may be used.
3. 50 Volts and above, AWG wire size MUST be used.

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