Introduction to Electric Shock Protection

This paper presents a general overview of the principles of electric shock and the systems of protection used to prevent it in electrical installation. Although mainly built around the United Kingdom Regulations, its principles can be applied to any country. The paper first discusses electric shock and the effects of electric current on the human body. It then outlines the types of earthing systems used. This then leads to the concept of an electric fault, how it develops and how it presents a dangerous condition to people. Protective devices are used to disconnect the supply in case of an electric fault, and these are discussed next. The most used system is the "Equipotential Bonding and Automatic Disconnection of Supply" system, which is further analysed. The paper then finishes by discussing the role of Residual Current Devices (RCD) in further electric shock protection.