Effects of 60-Hertz Current on Humans
Slight sensation on hand
Shock, not painful and muscular control not lost
Painful shock, painful but muscular control not lost
Painful and severe shock, muscular contractions, breathing
Ventricular fibrillation, threshold
Ventricular fibrillation, fatal (usually fatal for shock
duration of 5 seconds or longer)
Heart paralysis (no ventricular fibrillation), threshold
(usually not fatal; heart often restarts after short shocks)
Tissue burning (usually not fatal unless vital organs
The current values for women are lower because women typically have less body mass
4.3.2 Danger From Arcs and Blasts. Arcs result from the passage of electric current
through air. The air fails as an insulator but serves as a conducting medium for ionized gases.
Blasts result when the metal at the arc site expands and vaporizes. Arcs can reach temperatures
up to four times the temperature of the sun's surface. Water expands 1,670 times when it
becomes steam; copper expands 67,000 times when it vaporizes. High-energy arcs can be fatal
even at distances of 3 meters (10 feet).
Protection Against Hazards. Personal safety equipment prescribed by the
activity Safety Office should be used. It includes general body protection and safety tools and
equipment. Comply with OSHA standard 29 CFR 1910.269(i), Hand and Portable Power Tools.
4.4.1 General Body Protection. Always wear personal protective clothing as required
by your supervisor and as appropriate to the work area, work methods, and site hazards. Wear
these items because it is impossible or impractical to totally eliminate all work site hazards and
they will reduce your chance of injury or illness. OSHA standard 29 CFR 1926 Subpart E,
Personal Protective and Life-Saving Equipment covers this protection and indicates where it is
required. An example is where confined spaces or hazardous gases mandate respirators. A
summary of apparel requirements for general body protection is given in Table 2.