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Electricity. Related Work Activities . Using power tools Digging, excavating and boring Exposure to overhead power lines Falling branches Utility line tree trimming services. Hazardous Conditions & Unsafe Acts. Wet skin or damp ground
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Related Work Activities • Using power tools • Digging, excavating and boring • Exposure to overhead power lines • Falling branches • Utility line tree trimming services
Hazardous Conditions & Unsafe Acts • Wet skin or damp ground • Defective tools, cords, and electrical installations • Working near overhead lines • Digging near underground utilities • Taking electrical related risks • Not respecting the ability of electricity to kill
Potential Outcomes • What happens to you depends on how much, how long, and what part of your body the electricity goes through. • People have survived shocks of several thousand volts. • Others have been killed by voltages as low as 12 volts. • Prevention means not becoming part of the electrical flow.
OSHA Fatal Fact No. 57 • He received an electric shock that killed him. • Worker was climbing a metal ladder to hand an electric drill to a worker above him. • The extension cord had a missing grounding prong and that a conductor on the green grounding wire was making intermittent contact with the energizing black wire thereby energizing the entire length of the grounding wire and the drill's frame. • The drill was not double insulated.
Electrical Shock • Helping An Electrical Shock Victim • Call for immediate help. • Disconnect or de-energize the circuit. • Do not try to remove the victim from the current source! • Touching the victim could cause you to be shocked as well.
Path of Least Resistance • Grounding Electricity • If your body becomes part of the path, electricity will flow through it. • If that path is through vital organs like your heart and lungs you can die. • Grounding Electricity means creating an easy path for current that doesn’t include your body. Electricity always follows through the path of least resistance.
For Your Safety • Grounding Electricity • Electrical power tools should have a true ground or be double insulated. • Never cut off the third ground prong or use equipment with one of the three prongs broken. • If you feel a tingling sensation while you are using a tool, stop using the tool immediately. Take it out of service!
No Third Prong Here Either, Due to an Unauthorized Repair. Do Not Use!
For Your Safety-Continued • Grounding Electricity • Inspect wires and plugs on power tools before each use. • Replace damaged wires or plugs before using equipment. Do not splice wires or tape gashes. • Extension cords should be rated for outdoor commercial use. • Never leave a plug in a puddle or other collection of water.
Circuit Breakers • Protecting Equipment • Circuit breakers protect the wiring system from overloads. • If you become part of the circuit you may trip the breaker but it may be after a fatal amount of current flows through your body. • Circuit breakers do not protect people!
Ground-Fault Circuit Interrupters (GFCI) • Protecting People • Are designed to keep workers from being electrocuted. • If there is a short, the GFCI will quickly shut down the circuit. • A GFCI can be hard wired into an electrical box. • A portable GFCI can be plugged into any electrical outlet to protect you.
GFCIs • Portable GFCIs are common in landscaping • All extension cords must have a GFCI connected to them, including those running off of a generator.
Additional Information • http://www.osha.gov/OshDoc/data_Hurricane_Facts/elect_safety.pdf • OSH Answers: Electrical Safety - Basic Information • OSH Answers: Electric Tools - Basic Safety
Call Before You Dig • Failure to contact and locate utilities can lead to catastrophic events and large repair bills.
Planning-Prior to Digging • CALL BEFORE YOU DIG • Use your local one call system. • All underground utilities should be located. • Once located, utilities must be protectedfrom damage.
Overhead Electrical Hazards • Long, tall, or large equipment can come in contact with overhead power lines: • Ladders • Long-handled trim saws • Augers • Heavy equipment • Long poles or pipes
Power Line Clearance Distance from Power Lines 10 feet 15 feet 20 feet 25 feet 30 feet 35 feet Voltages < 50 kV 200 kV 350 kV 500 kV 650 kV 800 kV
Minimum Working Distances from Energized Conductors for Line-Clearance Tree-Trimmers
OSHA Fatal Fact • Workers were constructing a chain link fence in front of a house and directly below a 7200-volt energized power line. • They were installing 21-foot sections of metal top rail on the fence. • One employee picked up a 21-foot section of top rail and held it up vertically. • The top rail contacted the 7200-volt line, and the employee was electrocuted.
NIOSH Fatal Fact A landscaping crew felled a 65-foot oak tree, one of the branches caught onto the 69,000 volt power line. A landscaper was electrocuted and two workers seriously Injured
Additional Information • http://www.osha.gov/OshDoc/data_General_Facts/downed_electrical_wires.pdf • http://www.osha.gov/OshDoc/data_Hurricane_Facts/electrical_safety.pdf • OSHA Construction eTool: Electrical Incidents • Face report - http://www.cdc.gov/niosh/face/stateface/ca/93ca006.html
Material Handling and Storage Avoid Storing Materials Under Power Lines
For Your Safety • A knowledgeable person should assess each work site for safety hazards and design a work plan that addresses those hazards. • The employer should conduct a job briefing, based on the work plan, before starting work. • The employer should establish a written safety and health policy. • Safe tree removal techniques should be used. • Employers should notify the utility company when work is planned in an area near overhead power lines. • Employers and employees should become familiar with available resources on safety standards and safe work practices.
Remember These Important Points • Assume overhead power lines have no protective insulation and contact may be fatal. • Work as a team-One worker on the ground spots for the worker on raised equipment. • Electricity always seeks one or more paths of least resistance. • Never touch fallen overhead wires. • Notify the power company right away.
Remember These Important Points • Check for overhead power lines before doing any work. • Plan your route of travel to avoid power lines. • Make sure equipment does not contact power lines.
Most Important ! You, your equipment, and the materials you work with must stay at least 10 feet from power lines ! Note: Qualified line clearance tree-trimmers may follow rules which allow closer proximities.