VA is an abbreviation for volt-ampere, a designation of power in terms of volts and amperes.
VA stands for volt-ampere, a unit that designates power as the product of volts and amperes. In direct current circuits, volts times amperes gives the power in watts, but in alternating current circuits the volt-ampere expresses apparent power, the product of the voltage and current regardless of their phase relationship. Apparent power in volt-amperes can differ from the real power in watts when voltage and current are out of phase.
Because equipment such as transformers and power supplies must handle the full current and voltage regardless of phase, their capacity is often rated in volt-amperes rather than watts. The volt-ampere therefore describes the load a circuit and its cable must carry.
In commercial and industrial systems, volt-ampere ratings describe the capacity of equipment and the load on circuits. Recognizing the unit helps in understanding how power is specified and how cable must be sized to carry the current.
Because equipment such as transformers and power supplies must handle the full current and voltage regardless of phase, their capacity is often rated in volt-amperes rather than watts, so the volt-ampere describes the load a circuit and its cable must carry in alternating current systems.
At Windy City Wire, an understanding of power units, including the volt-ampere, supports the selection of cable sized for the load. Recognizing how volt-amperes describe apparent power helps customers match cable to the current that commercial and industrial circuits must carry.
VA (volt-ampere)