The Best Paper Award shines a light on some great papers. PSES is the source that professionals go to first for critical information on product safety engineering and compliance issues. So check out the Best Paper Nominees and think about a topic that could make you a winner!
Experiments of DC Human Body Resistance I: Equipment, Setup, and Contact Materials
Direct Current (DC) applications have become more prevalent in recent years, primarily due to the increased usage of renewable energy and energy storage systems. A review of the existing safety standards and other literature shows that there is limited experimental data on DC human body resistance. In particular, no information was found by the authors describing the repeatability of DC body impedance and the effect of contact material and other variables. The experimental work described here investigated DC human body resistance and the effects of electrode contact material, wet or dry conditions of the skin, and the repeatability of body impedance for a given set of test conditions. Three male adult volunteers participated in this study; each volunteer completed twenty sets of experiments, with each set including four different combinations of test conditions. The results show that the electrode material has an influence on the measured body impedance when the voltage was less than 15 V, supporting the supposition that the observed nonohmic behavior is attributable to Schottky effects. The variability of the tests (measured by the use of the coefficient of variance) is higher at lower voltage and drops as the voltage increases. Wet conditions were found to provide more consistent test results than dry conditions. Due to the improved measurement consistency and its lowered impedance relative to dry conditions, data under wet conditions are preferred for further analysis.