In our third installment of our four-part series on OSHA’s “Fatal Four” construction safety hazards we focus on electrocution hazards. Electrocutions accounted for 67 deaths in construction related accidents in 2011 which is the most current data available. According to OSHA this accounted for 9 percent of all construction related fatalities that year, the third most in the industry.
Electrocution is death by electric shock caused by exposure to lethal amounts of electrical energy. Electrocution can occur from contact with power lines, contact with energized sources such as faulty equipment or exposed wires and improper extension cord usage. Both overhead and underground power lines carry a high voltage. The best way to avoid electrocution from power lines is to simply stay away from them. By maintaining a safe distance and being aware of power line locations you can avoid making contact with heavy equipment, ladders, lifts, etc. If you do have to operate equipment such as cranes near power lines contact the utility company to de-energize and ground the lines. Other steps you can take to avoid electrocution around power lines include using nonconductive tools and equipment, never storing material underneath power lines and cordoning off the area around power lines to the correct distance per OSHA guidelines.
OSHA has also established rules and regulations regarding ground-fault protection. Receptacle outlets that are not part of the permanent wiring of the structure must be protected with ground-fault circuit interrupters (GFCIs). A GFCI monitors the electrical current flow from hot to neutral and if it detects an imbalance it will trip the circuit in less than a second and cuts off the electricity. You should also establish an assured equipment grounding conducting program that covers all cords, temporary receptacles, and equipment and maintain detailed records off all tests and inspections. Make sure all equipment and extension cords are in good condition by visually inspecting for cuts, frays or exposed bare wires and ensure that ground prongs haven’t been removed or become defective. You also want to make sure that the equipment grounding conductor is electrically continuous by conducting a continuity test.
Some of the most commonly cited standards by OSHA involving electrical hazards include:
Control of hazardous energy (lockout/tagout), general industry (29 CFR 1910.147)
Electrical, wiring methods, components and equipment, general industry (29 CFR 1910.305)
Electrical systems design, general requirements, general industry (29 CFR 1910.303)
Remember, death can occur from exposure to as little as 50 – 100 milliamperes of current. Most 120 Volt circuits carry 15 to 20 amperes of current. 15 amperes of current is 300 times what is necessary to cause death.
A great way to avoid accidental electrocution is to implement lockout/tagout procedures when equipment and circuits aren’t being used. A qualified person should ensure that all equipment and circuits are de-energized before a lock and/or tag is applied. Once you are ready to remove locks and tags and re-energize equipment and circuits a qualified person should be on hand to ensure that it is safe to do so.
Additional Electrical Hazards
There are a number of other electrical hazards that can cause serious injury or death in addition to electrocutions. These include burns, shock, arc flash or blast, fire and explosions. Some of the common causes for these other electricity related injuries include damaged equipment or faulty wiring, improper cord use, no GCFIs wet conditions, reversed polarity and lack of an assured grounding conductor program.
As was the case with our blog on Struck-by Hazards and Fall Hazards, this is not meant to be a definitive guide on electrocution hazards. It is intended to be an introduction to construction related electrocution and electrical hazards and safety measures to help prevent accidents they can cause. For more information on compliance with OSHA’s construction industry regulations, visit their website at http://www.osha.gov/doc/index.html.