Step and touch voltage – an update for 2004

Abstract

Hazardous step and touch voltages arise in a variety of high voltage electrical installations, and there are a number of different industry publications which publish acceptable step and touch voltage limits. This paper sets out the derivation of step and touch voltage limits based on the work of Dalziel and Biegelmeier and Lee, and AS/NZS 60479.1:2002. It then provides an outline of the different step and touch voltage limits used in current Australian guidelines, handbooks, and standards. There is a lack of consistent information available to utilities and designers to establish reliable step and touch voltage limits for different installations. This places the utilities and designers in a position of risk from litigation due to personal injury as the engineering models and guidelines in current use may not provide a robust defence. As a key step in risk management, this paper proposes further research to establish consistent and reliable step and touch voltage limits based on body shock currents, body impedance, and probability.