An Assessment of the 5-mA 60-Hz Contact Current Safety Level

This paper is an investigation into the research basis of the 5-mA electrical safety standard. Although Dalziel's let-go current research is generally considered to be the basis of this standard, the 5-mA level actually predates Dalziel's investigations. Nevertheless, in spite of some limitations in experimental design, Dalziel's let-go current experimental series is basically sound and well supports the 5-mA level as an occupational electrical safety standard. However, its applicability to the general population is questionable. Dalziel's data were developed from generally young, healthy subjects, and the standard's applicability to vulnerable populations such as children, the elderly, and the infirm is not known.