ABSTRACT
A three-phase supply provides 73% more power than a single-phase supply for the addition of a wire. Voltage variation – older electrical appIiances and equipment manufactured for UK operation at 240 volts should function perfectly well with European harmonised voltage power supply. Electrical installations required a separate fuse and isolator for each circuit. Electrical installations must be protected from current overload, otherwise appliances, cables and people using the equipment could be damaged. Polyvinylchloride (PVC) insulated and sheathed cable is now used for most electrical installations. Electrical installations must be tested on completion to verify that the system will operate efficiently and safely. Diversity in electrical installations permits specification of cables and overload protection devices with regard to a sensible assessment of the maximum likely demand on a circuit. Site electricity installations are temporary and will be subjected to ongoing alterations as site demands change.
