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11 electrical accident, Grounding • . secondary protectivemeasure to protect aga electric shock, It does notguarantee that you• get a shockor be injured or ^• by an electrical current, It will, however, substantially reduce the risk, especially when used in combination with other safety discussed in this booklet, 29 CFR, Part 1910.304, Subpart S, Wiring Design and Protection, requires at times a service or system ground and an equipment ground in non -construction applications. A service or system ground is designed primarily to protect machines, tools, and insulation against damage. One wire, called the " neutral" or " grounded" conductor, is grounded. In an ordinary low -voltage circuit, the white or gray wire is grounded at the generator or transformer and at the building's service entrance. An equipment ground helps protect the equipment operator. It furnishes a second path for the current to pass through from the tool or machine to the ground. This additional ground safeguards the operator if a malfunction causes the tool's metal frame to become energized. The resulting flow of current may activate the circuit protection devices. -0037= Circuit protection devices limit or stop the flow of current automatically in the event of a ground fault, overload, or short circuit in the wiring system. Well-known examples of these devices are fuses, circuit breakers, ground -fault circuit interrupters, and arc -fault circuit interrupters. Fuses and circuit breakers open or break the circuit automatically when too much current flows through them. When that happens, fuses melt and circuit breakers trip the circuit open. Fuses and circuit breakers are designed to protect conductors and equipment. They prevent wires and other components from overheating and open the circuit when there is a risk of a ground fault. Ground -fault circuit interrupters, or GFCIs, are used in wet locations, construction sites, and other high-risk areas. These devices interrupt the flow of electricity within as little as 1/40 of a second to prevent electrocution. GFCIs compare the amount of current going into electric equipment with the amount of current returning from it along the circuit conductors. If the difference exceeds 5 milliamperes, the device automatically shuts off the electric power. Arc -fault devices provide protection from the effects of arc -faults by recognizing characteristics unique to arcing and by functioning to deenergize the circuit when an arc - fault is detected. What work practices help protect you against electrical hazards? Electrical accidents are largely preventable through safe work practices. Examples of these practices include the following: deenergizing electric equipment before inspection or repair, keeping electric tools properly maintained, exercising caution when working near energized lines, and using appropriate protective equipment.