Facilities Manager's Desk Reference, 3rd Edition

18Electrical Supplies and Electrical Safety

18.1 Introduction

There are many different ways to make electricity. Each method involves the use of a turbine to spin and convert kinetic energy into electricity. A turbine is a type of engine that can extract energy from a fluid, such as water, steam, air or combustion gases. Electricity is made when a turbine moves a large magnet around a very large wire. Three coils are set around the magnets and the movement serves to electrify the wire. This generates three‐phase supplies – referred to as red, blue and yellow. Each phase is 230 V supply. Electricity is then pushed away from this generator through special transformers. Steam, combustion gases and water are commonly used to turn industrial turbines for the creation of electricity.

Electricity behaves like water – it flows. It therefore follows the path of least resistance. If resistance is encountered, then the energy is discharged. The further the electricity has to travel from where it is made to where it is used, the more resistance and loss of energy occurs. It is more efficient to create electricity nearer to the point of use. Combined heat and power (CHP) plant, solar panels and photovoltaics are examples of locally produced electricity.

Electricity is provided to buildings as either low‐voltage supplies or high‐voltage supplies. ‘Low voltage’ is a term used to describe the 400 V three‐phase and 230 V single‐phase supplies. These low‐voltage supplies normally come directly ...