Electrical Hazards and the Importance of Safety
Working with electricity can be dangerous. Engineers, electricians, and other professionals work with electricity directly, including working on overhead lines, cable harnesses, and circuit assemblies. Others, such as office workers, work with electricity indirectly and may also be exposed to electrical hazards.
Electricity has long been recognized as a serious workplace hazard. Cal/OSHA's electrical standards and UC Davis policies are designed to protect staff and students from the dangers of being exposed to electric shock, electrocution, fires, and explosions.
Procedures for Electrical Work and Use of Electrical Equipment
1. Appropriate applications for extension cords. Extension cords may be used to supply power to appliances under limited conditions. These include:
a. Temporary situations such as laboratory experiments lasting no longer than 90 days.
b. Situations in which permanent wiring is inappropriate because equipment is moved frequently.
c. Power tools or other portable appliances used on a transient basis.
2. Proper selection and use of extension cords
a. Plug must be three-pronged, in good condition and appropriately sized for the anticipated load.
b. Must be free of splices, repairs, and signs of excessive wear.
c. Must not pass through doors or windows.
d. Must not be stapled or attached to a floor, wall, or ceiling.
e. Must not be connected in series.
f. Must not create a tripping or other safety hazard.
g. Must be protected where exposed to foot or wheel traffic to minimize tripping hazards and damage to the cords.
h. Must have built-in overload protection if there is more than one outlet.
3. Use of multiple-outlet surge protectors
a. Must be equipped with an automatic circuit breaker. Outlet strips with fuses or without overcurrent protection are not acceptable.
b. Must be equipped with an indicator light. If the indicator light is off but the protector’s outlets have power, the unit has failed and must be replaced.
c. Must have a cord no more than 15 feet long and must be directly plugged into a wall receptacle or into a hard-wired (not merely plugged in) overhead corded set of outlets. Hard-wired overhead corded sets of outlets must be fitted with strain relief fittings at the point of support. Use of surge protector power strip products with cords longer than 15 feet (up to UL’s maximum 25 feet) must be approved by UC Davis Fire Department.
d. Must be protected where exposed to foot or wheel traffic, furniture, or equipment to minimize tripping hazards and damage to the cords.
e. Must not be connected in series.
f. Review original packaging to determine whether the power strip may be used for tools or small appliances. Maintain documentation to verify your application is appropriate.
g. Under no circumstances may you plug-in higher wattage appliances such as coffeepots, space heaters, microwave ovens, hot plates, full-size refrigerators, or copy machines.
h. Plug mold or "U" mold style power strips permanently installed on a wall and hard-wired into the campus electrical system are a fixed power strip, installed and maintained by the University, and not subject to the same restriction as portable power strips.
4. Equipment in patient care areas
a. Portable equipment for use in patient care or clinical laboratory areas must have a hospital-grade plug.
b. Personally owned line-powered devices are not allowed in designated patient care areas.
5. Electrophoresis equipment
Electrophoresis equipment must have a lid or cover with safety interlocks to prevent accidental contact with energized electrodes or buffer solutions. The equipment must be labeled "WARNING [OR DANGER]--ELECTRICAL HAZARD." Power supplies must only be operated in accordance with the manufacturer's written directions.
6. Damp or wet locations: greenhouses, animal rooms, around swimming pools and fountains, and similar locations
Equipment in wet areas must be designed and approved for use in damp locations. When it is not possible to ensure protection from contact with water, the equipment must be protected by a ground-fault circuit interrupter (GFCI). Equipment used for large construction projects or for projects outdoors that may be exposed to rain or wet conditions must be protected by ground-fault circuit interrupters.
7. Fire prevention and combustible materials
Place heat-producing equipment at a safe distance from combustible materials such as paper, cardboard, wood, and plants. Combustible containers shall be properly grounded and transfer containers bonded (connected by cable) to the storage equipment (i.e. tank, drum).
8. Tripped circuit breakers
Report all problems with tripped electrical circuit breakers to Facilities Management at (530) 752-1655. Facilities Management should be the only department working within electrical panels or load-rated switchgear. Tripped circuit breakers can indicate a serious electrical hazard.
9. Damaged equipment, plugs, and cords
Equipment with damaged plugs or cords or other conditions that constitute an electrical hazard must be removed from service until repaired.
10. Electrical distribution panels, load center panels, safety disconnect switches and distribution transformers
a. Electrical distribution panels, load center panels, safety disconnect switches and distribution transformers should not be blocked with anything stored on the floor or on the wall beneath the panel. A minimum three foot clearance shall be maintained to the front and sides of panels.
b. No combustible materials such as paper, cardboard, wood and flammable solvents shall be stored on or close to the transformers and other electrical equipment that inherently generate heat.
11. Restrictions on use of UL (or equivalent) listed equipment
a. Use of equipment must be consistent with the restrictions of the certification. In many cases when equipment is certified by a testing laboratory such as UL, there are restrictions on the use of the equipment. The restrictions are listed on the equipment label adjacent to the UL listing. For example, equipment may be certified only for home use or only for use when mounted vertically.
b. Retractable cord reels or any reeled cord must be fully unreeled during use to avoid heat build-up.
c. “Interior Use” rated cords must not be used outdoors.
d. “Exterior Use” rated cords are designed to withstand normal exposure to sunlight and moisture and may be used inside or outside a building.