Ampere the watt, the ohm and the volt. Rather than a definition in terms of the force between two current-carrying wires, it has been proposed that the ampere should be defined in terms of the rate of flow of elementary charges. Since a coulomb is approximately equal to elementary charges (such as those carried by protons, or the negative of those carried by electrons), one ampere is approximately equivalent to elementary charges moving past a boundary in one second. ( is the reciprocal of the value of the elementary charge in coulombs.) The proposed change would define 1 A as being
Electrical conductor American wire gauge article contains a table showing allowable ampacities for a variety of copper wire sizes The ampacity of a conductor, that is, the amount of current it can carry, is related to its electrical resistance: a lower-resistance conductor can carry a larger value of current. The resistance, in turn, is determined by the material the conductor is made from (as described above) and the conductor's size. For a given material, conductors with a larger cross-sectional area have less resistance than conductors with a smaller cross-sectional area. For bare conductors, the ultimate limit is the point at which power