Electric Shock Thresholds & Body Resistance: Expert Data from MIT, Bussmann, and Dalziel Studies

The following table summarizes the thresholds at which electric current becomes perceptible, involuntary, or lethal, based on data from the Massachusetts Institute of Technology (MIT) safety page and the Cooper Bussmann, Inc. safety handbook.

Both sources credit Charles F. Dalziel, a pioneer in the study of human electrical responses. While the MIT table lists a DC perception threshold for men at 5.2 mA, Dalziel’s table reports 6.2 mA, and for the 60 Hz AC “unable to let go” threshold the values differ (MIT: 20 mA, Bussmann: 16 mA). The lower figures are used here for safety.

These modest currents illustrate how even tiny amounts of electric flow can be hazardous.

Body resistance data, sourced from the Lawrence Livermore National Laboratory’s safety document (Human Electrical Sheet) and Ralph H. Lee’s 1971 IEEE Spectrum article, provide resistance values for key contact points.

Dalziel’s original experiments at the University of California, Berkeley, involved volunteers holding a copper wire and placing the other hand on a brass plate while a voltage was applied. Currents were incrementally increased to determine the maximum tolerable level and the point of involuntary muscle contraction. Over two dozen volunteers participated, and subsequent animal studies examined heart fibrillation.

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