Voltage regulation of cables used IOR low voltage A-C distribution

DISTRIBUTION of alternating current at low voltages does not depend primarily upon the selection of a conductor size which is thermally adequate, but depends upon the voltage regulation limits which will be satisfactory for lighting, especially when combined lighting and power loads are carried on the same circuit. Voltage regulation of a-c circuits is a function of the magnitude of the current, the power factor, and the circuit impedance. With currents of lower power factor, the inductance component of the impedance becomes the major parameter affecting the voltage regulation, and for a particular circuit and load, there is an optimum ratio of resistance to reactance. While the resistance per unit length of circuit is variable, depending only upon the physical size of the conductor, the reactance per unit length is almost independent of the physical size of the conductors, and for a single circuit with cables, can be changed only by changes in cable construction.