Overhead and Underground Power Line Safety Quentin Baker

Overhead and Underground Power Line Safety Quentin Baker Director of Safety 513 -5463 516 -7456 1

Overview ü Background on power lines ü Hazards of overhead and underground power lines ü Injury prevention techniques ü Summary 2

Background • Power lines transmit electricity • Electrical current exposes workers to serious hazards – Most common hazard is electrocution – Most workers are unaware of potential electrical hazards • Power lines can be – Overhead – Underground Utility 3 Wor

Background (cont) • Some activities may cause interference with power lines – Overhead power lines • Operation of a crane, forklift, and other construction equipment • Changing street lights • Tree trimming • Caution: Look out for overhead power lines when operating equipment – Underground power lines • Excavation 4

Types of Electrical Lines • Electrical Cables – High Voltage, Low Voltage – Supervisory and Signaling Cables – Cathodic protection (cabinets, cables, earthing conductors, cable shrouds) • Communication Cables – – – Phone lines Coaxial cables (e. g. data cables) Broadband cables Tram traction cables and trolley wires Railway supply cables and traction wires 5

Power Line Hazards When unloading materials, watch out for overhead power lines Fire may be caused after 6 overhead power lines are hit

Common Misconceptions • Birds land on power lines, so they must be safe to touch - NO The power lines are safe for perching, but not when struck – Main objective of electricity is to reach the ground using the most direct route – Birds do not get electrocuted when they land on wires because they do not represent a path to the ground 7

Common Misconceptions • Power lines are insulated, so they are safe to touch - NO – They are not always insulated • Insulation deals with placing nonconductive material around the wire • Insulation is a material that offers high electric resistance making it suitable for covering wires to prevent the possible future contact of adjacent conductors resulting in a short circuit – Just because a wire is weather protected does not mean that it is insulated • Weather protection prevents water and snow from reaching the wire (and insulation, if used) 8

Common Misconceptions (Cont) • Nonmetallic ladders are safe around power lines - NO – Wet ladders can be a conducting medium for electricity • If power lines are not touched, they are safe NO – Electricity can jump 9

Hazard Identification • Conduct site investigation to identify existing conditions of: – Voltages of lines and equipment – Presence of hazardous, induced voltages – Presence and condition of protective grounds and equipment grounding conductors – Locations of electrical circuits and equipment – Maximum switching transient voltages 10

Dump truck operators should use caution when unloading materials near overhead power lines 11

Injury Prevention Techniques • Stay away from power lines while working • Maintain a safe distance • OSHA’s “ 10 -Foot Circle of Safety” rule • Increase safe distance near higher voltage Maintain a safe distance from the power lines Danger Zone (10 foot radius from the power line) 12

Operation Clearances for Energized Overhead Lines Nominal Voltage Minimum Required Distance (Feet) 0 to 50, 000 10 Over 50, 000 10+0. 4 inch for each 1, 000 volt “In Transit” Clearances for Energized Overhead Lines Nominal Voltage Minimum Required Distance (Feet) 0 to 50, 000 4 50, 000 to 345, 000 10 Over 345, 000 to 750, 000 16 13

Injury Prevention Techniques • Recognize high voltage power lines – If unknown, the appropriate agency should be contacted • Inform others about high-voltage power lines Be aware of nearby highvoltage power lines 14

Injury Prevention Techniques • Examine the site – Be mindful of power lines • Search carefully around the site • Look for lines not seen due to obstructions • Alert others at the pre-job briefing • Assume all lines are energized and potentially dangerous • Make a safety clearance boundary – Portable safety barriers HAZARD: Safe distance has not been maintained 15

Injury Prevention • Use a spotter – Equipment operators have limited visibility – Get spotter’s help to stay clear of overhead power lines • Spotter’s job should only require spotting and NOT guiding – Guiders may be at risk of electrical shock • Especially when using a tag line A spotter guiding heavy equipment operator 16

Injury Prevention • When working with tall and long equipment – Carefully plan and organize work with heavy equipment – Keep vehicles clear of power lines – Watch out for long objects – Adjust the position of equipment to maintain a safe distance from power lines Working with tall equipment 17

Injury Prevention Down power lines are dangerous 18

Injury Prevention • Fallen power lines can cause fires Fire caused by fallen power line • If a co-worker makes contact with a power line – Stay away – Protect yourself • You could be shocked too if you touch someone who is in contact with electricity 19

Injury Prevention • If you hit a power line – In case of no immediate danger • Move the equipment away • Have someone call 911 • Stay on the equipment until you know it is safe. • Warn others to stay away – If you MUST get off the equipment, jump clear Crane hitting a power lin 20

Underground Power Lines • Hitting a buried power, gas or communications line can cause – Injury – Excessive cost of repair • Plan the work ahead • Call the utility company With proper planning, these types of mistakes can be avo 21

Underground Power Lines • Locate and mark the perimeter of underground lines • Exercise caution when excavating near power lines - Some manual excavation may be required • Stay away from pad mount transformers – Green metal box • Underground utility line that has been hit 22

Tree Trimming • Trees that grow into power lines can cause unnecessary power outages • Trees planted under or near power lines are potentially dangerous hazards • Before tree trimming, check for the power lines • Use proper equipment and trained personnel • Tree trimming may be dangerous if power lines are hidden in the foliage 23

Applicable Standards 29 CFR 1926, Subpart K – Electrical 29 CFR 1926, Subpart N – Cranes, Derricks 29 CFR 1926, Subpart O – Motor Vehicles, Mechanized Equipment 29 CFR 1926, Subpart P – Excavations 1926. 416 Electrical Hazards 1926. 955 Overhead Lines 1926. 956 Underground Lines 24

Summary… • Working in proximity of overhead and underground power lines is hazardous – Most common hazard is electrocution • Workers should be aware of such hazards • Several injury prevention techniques should be exercised to prevent injuries and fatalities – Need sufficient training to understand the hazards and practices for injury prevention – One of the best ways of hazard elimination is maintain a minimum safe distance • Properly locate underground power lines before starting of work 25

Conclusion • Thank you for attending today’s training, if you have questions for discussion I am available after the session or I maybe reached at: (336) 513 -5463 • Please make sure you signed onto the Training Roster. • Remember: Plan your Work and Work your Plan 26