Kiloamperes

A kiloampere (kA) is the unit of electric current equal to 1,000 amperes. It uses the SI prefix kilo- with the ampere, and the standard symbol is kA.

Kiloamperes are used for high-current applications where currents reach thousands of amperes, such as electric power transmission and distribution, large transformers, busbars, motor drives, and protection equipment. They also appear in fault-current calculations and system studies to represent potential short-circuit currents.

In practice, equipment ratings and measurements are often expressed in kiloamperes. The basic conversion is 1 kA = 1,000 A and 1 A = 0.001 kA. The choice of unit depends on the scale of the system and the convention used in a given installation or standard.

In electrical engineering, kA is commonly encountered in ratings for circuit breakers, fuses, switchgear, and conductors. A circuit or component may be specified by its maximum interrupting or carrying current in kiloamperes, such as a device rated for a certain kA fault-current level. This rating helps determine protection settings, conductor sizing, and overall system safety.

Notes on terminology: kiloamperes measure instantaneous current, not energy. They are related to ampere-hours (Ah) or kilowatt-hours (kWh) only indirectly through time and voltage in energy calculations.