Electrical hazards: their causes and prevention

Tooley, Mark

doi:10.1016/j.mpaic.2007.08.019

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Volume 8, Issue 11 , Pages 461-463, November 2007

Electrical hazards: their causes and prevention

Mark Tooley, PhD, is Consultant Clinical Scientist at the Royal United Hospital, Bath, UK, and head of the department of Medical Physics and Bioengineering. He is an Honorary Senior Lecturer at the universities of Bath and Bristol. He is a Chartered Engineer and Scientist, and is a fellow of the Institute of Physics and Engineering in Medicine (IPEM), the Institute of Physics (IOP) and the Institution of Engineering and Technology (formerly IEE). He is an affiliate of both the Royal College of Physicians and the Royal College of Anaesthetists

Abstract

Electrical injury is caused by current passing through the body. The source of the current is normally from the domestic mains supply, which in the UK is alternating at 50 Hz (cycles a second), at a voltage of 230 RMS (root mean square). The damage and injury to the body are proportional to amount of current through the body, and the current density. The paper discusses the basis of electrical safety, introducing the safety philosophy of the mains supply. Leakage currents and how multiple earth faults can be very dangerous, especially in microshock, are discussed. The prevention of hazards is covered, looking at supply isolation, circuit breakers, residual current devices, and safety standards.

Keywords: electrical safety, earth faults, microshock, prevention of electrical hazards, safety standards