Electrical Equipment

The most common physical and fire hazards come from electrically powered devices. Electrically powered equipment is used routinely in university offices, laboratories and shops. The majority of injuries associated with electrically powered equipment occur from electrical shock. An electrical shock injury can occur if a person is exposed to a current as low as 10 milliamperes (mA). Exposure at levels of 80 to 100 mA can be fatal. Electrical equipment can also serve as an ignition source for combustibles materials, flammable or explosive vapors. Many of the risks can be minimized by following rules for the safe use of electricity and proper maintenance of electrical equipment.

  • Understand the nature of all electrical equipment and maintain it in proper and good working condition.

  • Be certain your hands and the floor of your work area are dry before touching electrical equipment or connecting cords.

  • Learn where the disconnect switches or circuit breakers are for your area (ensure that others using equipment also know this).

  • Routinely examine all wiring, plugs, temporary power taps (multiple-plug outlets), and extension cords for any signs of exposed wire or deteriorating insulation.

  • If a piece of equipment gives a shock, no matter how minor, tag it "out of order" and have it repaired by a certified electrician.

  • Never override fuses, circuit breakers, or interlock switches.

  • Purchase or have an electrician modify drying ovens or high-temp furnaces/ovens to have thermal runaway protection.

  • Extension cords shall consist of UL approved round cord with three separate insulated wires and 3-pronged connectors in good condition (no nicks or cuts).

    • Extension cords can only be used for temporary work conditions (< 3 days). If longer periods of use are needed, temporary power taps may be used.

    • Keep all cords off walkway floors where they can become tripping hazards or be damaged. Protect cords by running them along perimeter walls or enclosing in protective covers. The covers will keep the cords from becoming tripping hazards.

    • Extension cords shall service only a single piece of electrical apparatus.

    • Extension cords shall not be used in conjunction with refrigerators, portable heaters, irons, or similar heat producing devices.

    • Extension cords shall not be used where flammable vapors, gases, or explosive dusts are present.

    • Extension cords are not a substitute for permanent wiring. They shall not be used through walls, doorways, ceilings, floors, etc.

  • Temporary power taps are frequently referred to as multiple-plug outlets. These electrical devices can be used when insufficient electrical receptacles are available for office and certain laboratory activities. The devices usually have three to six electrical receptacles, a circuit breaker, and a cord that is usually 6 feet in length but can be obtained in 12-foot and 15-foot lengths. The devices can be obtained with a surge protector.

    • Multiple-plug outlets must be UL-approved.

    • Multiple-plug outlets shall not be used in conjunction with refrigerators, portable heaters, coffee pots, or similar heat producing devices.

    • Multiple-plug outlets shall not be used where flammable or explosive atmospheres exist.

    • The cords to multiple-plug outlets should be kept off walkway floors where they can become tripping hazards or be damaged. Protect cords by running them along perimeter walls or enclosing in protective covers. The covers will keep the cords from becoming tripping hazards.

    • Multiple-plug outlets must be plugged directly into mounted electrical receptacles. They cannot be daisy-chained together.