ABSTRACT
An important aspect of both single-phase and three-phase distribution systems is grounding. Two grounding methods, system grounding and equipment grounding, will be discussed in this chapter, along with ground-fault protective equipment. Most electrical power, when produced at the power plants, is produced as three-phase AC voltage. Electrical power is also transmitted in the form of three-phase voltage over long-distance power-transmission lines. At its destination, three-phase voltage can be changed into three separate single-phase voltages for distribution into the residential areas. Although single-phase systems are used mainly for residential power distribution systems, there are some industrial and commercial applications of single-phase systems. Single-phase power distribution usually originates from three-phase power lines; so electrical power systems are capable of supplying both three-phase and single-phase loads from the same power lines. To meet the demand for more residential power, the single-phase three-wire system is now used.
