A circular mil (often abbreviated as cmil or kcmil) is a unit of area used primarily in the United States for measuring the cross-sectional area of a round wire or cable. It is a convenient unit for specifying the size of electrical conductors.
One circular mil is equal to the area of a circle with a diameter of one mil (1/1000th of an inch) or approximately 0.000000506707 square inches (in²). In metric units, one circular mil is approximately equal to 0.000001273 square millimeters (mm²).
Circular mils are commonly used in the American Wire Gauge (AWG) system to specify wire sizes. The AWG system assigns a unique number to each wire size, and this number is related to the wire's cross-sectional area in circular mils. For example, a larger AWG number corresponds to a smaller wire size with fewer circular mils, while a smaller AWG number corresponds to a larger wire size with more circular mils. This system allows for easy reference and selection of wire sizes for various electrical applications.
An acre (ac) is a unit of area commonly used in the United States and some other countries, especially for measuring land area, particularly in the context of real estate and agriculture.
One acre is equivalent to 43,560 square feet or 4,840 square yards. In terms of square meters, it is approximately 4,046.86 square meters.
To provide some perspective, an acre is roughly the size of a football field, excluding the end zones. It is a common unit for describing land area in rural and suburban areas, as well as for determining the size of plots of land, farms, and other land parcels.