Electrical Safety Recognizing & Controlling Hazards
Introduction Healthcare facilities, including hospitals, physician offices, laboratoratories, dental offices and beyond are vulnerable to a variety of potential occupational dangers. Electrical hazards are one such potential danger, and they shouldn t be ignored. Electricity must always be treated with the respect it deserves to avoid workplace casualties, including electric shock, electrocution, burns, fires and explosions.
Definitions Electricity: electric current used or regarded as a source of power Current: the amount of electric charge flowing past a specified circuit point per unit time Circuit: a closed path followed or capable of being followed by an electric current Conductor: a substance or medium that conducts heat, light, sound, or especially an electric charge Ground: a large conducting body, such as the earth or an electric circuit connected to the earth, used as an arbitrary zero of electrical potential
Definitions Con t Electrical Shock: the physiological reaction, characterized by pain and muscular spasm, to the passage of an electric current through the body; it can affect the respiratory system and heart rhythm Electrocution: to kill with electricity Live Wire: a wire carrying an electrical current Voltage: a measure of the difference in electric potential between two points in space, a material, or an electric circuit, expressed in volts Receptacle: a fitting connected to a power supply and equipped to receive a plug
Electrical Shock Occurrence Electrical shock occurs if part of your body completes an electrical circuit by: touching a live wire and an electrical ground, or touching a live wire and another wire at a different voltage It takes only a surprisingly small amount of electricity to cause death. Short of death, electricity also causes burns and electrical fires.
Basic Electrical Safety Model The National Institute for Occupational Safety and Health, or NIOSH, created the Basic Electrical Safety Model, consisting of three easy-to-follow steps: 1. Recognize Hazards 2. Evaluate Hazards 3. Control Hazards
Step 1: Recognize Hazards A typical 15 amp electrical outlet provides well over the amount of current necessary to cause electrocution. Know which situations can render you vulnerable. Look for danger associated with: Inadequate wiring Exposed electrical parts Wires with bad insulation Electrical systems and devices that are not grounded or double insulated Overloaded circuits Damaged power devices and equipment Use of an incorrect device Wet location, equipment or healthcare worker
Step 2: Evaluate Hazards Once hazards have been recognized, they must be evaluated for resultant personal risk. Judgment is involved with this step, and evaluation of risk must be performed on an ongoing basis. The following are conditions, or clues, indicative of a potential hazard: Tripped circuit breakers and blown fuses are determinant of too much current following in a circuit. This situation could be due to several factors such as malfunctioning equipment or a short between conductors. An electrical device, appliance, wire or connection that feels warm may indicate too much current in the circuit or equipment.
Step 2: Evaluate Hazards, Con t. An extension cord that feels warm may indicate too much current for the cord s wire size. A cable box, fuse box, or junction box that feels warm may indicate too much current in the circuits. A burning odor may indicate overheated insulation. Worn, frayed, or damaged insulation around a wire or other conductor is an electrical hazard because the conductors could be exposed. Contact with an exposed wire could cause a shock. Damaged insulation could cause a short, leading to arcing or a fire. Inspect all insulation for scrapes and breaks. A GFI that trips indicates there is a current leakage from the circuit.
Step 3: Control Hazards Controlling hazards is a two-part process. First, create a safe work environment, and then work safely within it. Make your environment safer by doing the following: Treat all wires (even de-energized ones) as if they are energized until they are unplugged, or locked out and tagged. Lock out and tag out circuits and machines that cannot be controlled by simply unplugging When extension cords are used on a temporary basis, prevent overloaded wiring by using extension cords of correct size. Prevent exposure to live electrical parts by making sure they are isolated.
Step 3: Control Hazards Cont. Prevent exposure to live wires and parts by making sure they are insulated. Prevent shocking currents from electrical systems and tools by making sure they are grounded. Prevent shocking currents by using Ground Fault Interrupters or GFIs. Prevent too much current in circuits by using overcurrent protection devices.
GFIs GFI stands for ground fault interrupter, with a ground fault being an unintentional electrical path between a power source and a grounded surface. GFIs are inexpensive lifesavers, electrical devices that can either be installed in an electrical system or built into a power cord to protect from severe electrical shock. They play an important role in healthcare workplaces. Greater use of GFIs could further reduce electrocutions and mitigate thousands of electrical burn and shock injuries at home and in healthcare workplaces each year. GFIs are particularly recommended in bathrooms, garages, outdoor areas, crawl spaces, unfinished basements, kitchens, and near wet bars.
Improper Grounding The improper grounding of equipment and circuitry is the most common OSHA electrical violation. When an electrical system is not grounded properly, a hazard exists. Metal parts of motors, appliances, or electronics that are plugged into improperly grounded circuits may be energized. When a circuit is not grounded properly, a hazard exists because unwanted voltage cannot be safely eliminated. If there is no safe path to ground for fault currents, exposed metal parts in damaged appliances can become energized. Replacing metal plumbing with plastic in some situations can interrupt the path fault current may take and thus result in electrocution and/or fire. The metal parts of electrical equipment that we touch should be grounded and at zero volts.
Extension Cords Errant extension cord use, sometimes in place of permanent wiring, poses an electrical hazard. Extension cords are not permitted to be used as a substitute for the fixed wiring of a structure. The size of wire in an extension cord must be compatible with the amount of current the cord will be expected to carry. Using the right extension cord is one way to create a safe work environment. The length of the extension is also important because voltage drops over the length of a cord. The grounding path for extension cords must be kept intact to preserve your safety.
Live Parts Prevent injuries from contact with live parts by: Immediately reporting exposed live parts to a supervisor or qualified person. Unqualified persons should never attempt to correct the condition themselves. Ensuring that guards or barriers are installed if live parts cannot be enclosed completely. Ensuring that covers, screens, or partitions for guarding require tools to remove them. Ensuring covers that have been removed from panels, motors, or fuse boxes are replaced. Work on electrical service panels is reserved for qualified persons.
Live Parts Cont. Taking care when using objects like metal rods or pipes that can contact even appropriately elevated live parts. Ensuring unused openings in electrical boxes are closed so that foreign objects (pencils, metal clips, conductive debris, etc.) cannot get inside and damage the circuit.
Authorities and Standards OSHA s general industry electrical safety standards are published in Title 29 Code of Federal Regulations, Part 1910.302 through 1910.308-Design Safety Standards for Electrical Systems, and 1910.331 through 1910.335-Electrical Safety-Related Work Practices Standards. OSHA s electrical standards are based on the National Fire Protection Association Standards NFPA 70, National Electric Code (or NEC), and NFPA 70E, Electrical Safety Requirements for Employee Workplaces. When OSHA regulations and the NEC are followed, safe work environments are created. OSHA standards focus on the design and use of electrical equipment and systems to minimize electrical hazards. Additionally, certain approved testing organizations are required to test and certify electrical equipment before use in the workplace to ensure its safety.