Survey of Electrical Utility Worker Body Impedance

A survey of electrical utility worker body impedance was conducted using a contact-current meter. Measurements of body pathway impedance for all hand and foot combinations were made on 191 male and 40 female Southern California Edison employees. Measurements were log-normally distributed for men and women for all pathways. Values for men and women were statistically significantly different. Internal pathway impedance was generally well correlated with body mass index, while total pathway impedance was not. Repeat measurements on three volunteers showed the measurement methodology to be highly reproducible. The results varied somewhat from those compiled in the 1930s and 1980s and used in the IEEE and IEC standards. The differences may be attributed to changes in BMI over time, the different voltages and frequencies used by different investigators, and the techniques of measurement. However, the measurements were generally compatible with older data, but additional measurements under different conditions are necessary to confirm their application.