812 OSHA Focus Four Hazards

Examples

To further illustrate how easily a person can receive a fatal shock, consider a voltage that is common to every location in the United States, 120-volts. Under average working conditions where a person is perspiring, they have a resistance of only 1000 ohms from hand-to-hand. Using the simple Ohm's Law formula (current equals the voltage divided by the resistance), the current flow will be 0.12 amperes or 120 mA. From the table in the previous section, we can see that the reaction can be a painful shock to possible death.

A fault current may travel through a worker's body, causing electrical burns or death if:

• the power supply to the electrical equipment is not grounded, or
• the path has been broken, or
• if there are live parts or bare wires.

Even when the power system is properly grounded, electrical equipment can instantly change from safe to hazardous because of extreme conditions and rough treatment.

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