OSHA Construction · Part 5
Electrical Safety in Construction
How electric current injures, the grounding, GFCI and lockout measures that prevent it, and the work practices that keep construction workers safe near power lines, tools and cords.
Pages in this chapter (1 of 2)
5.1 The Dangers
OSHA's electrical standards deal with the dangers for people who work on, near or around electricity: electric shock, electrocution, burns, fires and explosions. They specify safe design features for installing and using electrical equipment and systems.
- More than five workers are electrocuted every week in the United States.
- Electricity causes about 12 percent of work deaths of young workers.
- Very little current flowing through the body can cause harm.
- Electrical faults cause serious fires.
| Term | Meaning |
|---|---|
| Current | The flow of electrons, measured in amperes (amps). |
| Volts | The electrical pressure. |
| Watts | A measure of the work done by an electrical circuit. |
| Resistance | Opposition to the flow of current. |
| Conductor | A material with free electrons that lets current flow. |
| Insulator | A material with few free electrons, through which current hardly flows. |
| Circuit | The complete path of the current: a voltage source, conductors and the load. |
| Electric shock | The effect on nerves and muscles of current flowing through the body. |
| Electrocution | Death caused by electric shock. |
| Grounding | A deliberate conductive connection to earth that gives any fault current a path back to the source. |
| GFCI | A ground fault circuit interrupter detects a difference between the current in the circuit conductors and the ground. If a leak as small as 5 milliamps lasts for as little as one fortieth of a second, it cuts the circuit and prevents a shock that most people would not even feel. |
| AWG | American wire gauge, a standard for the size of wire. |
Types of injury
- Direct: electrocution; electric shock and its effects, such as broken bones and neurological disorders; burns; and arc flash or blast, which causes burns and concussion.
- Indirect: falls, back injuries and cuts to the hands, caused by the reaction to the shock.
Page 1 of 2 in this chapter · page 14 of 29 in the book
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