1. Electricity

2. Related Work Activities
Using power tools
Digging, excavating and boring
Exposure to overhead power lines
Falling branches
Utility line tree trimming services

3. 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

4. Unsafe Work Practices can be Deadly!

5. 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.
A non-fatal flow is referred to as a shock
A fatal flow is an electrocution
Any level of flow through the chest cavity can be deadly.

6. Non-Fatal Shocks can Result in Severe Burns

7. 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.

8. 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.

9. 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.

10. 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!
For example, a drill has a third wire incorporated in the design. This third wire acts as the ground wire. This means the current will follow the ground wire --- not the operator. Usually a three-prong plug in a three-hole outlet provides a proper ground.

11. Danger! Missing Ground Prong
Note: Defective cord.

12. No Third Prong Here Either, Due to an Unauthorized Repair. Do Not Use!

13. 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.
Shield plugs and outlets. Protect plugs and outlets from moisture in the environment. Extension cords are for temporary use. Have permanent wiring installed where needed. Where equipment cord plugs into an extension cord, tie a half-knot to keep the plug from pulling out. Only use one hand when touching plugs, outlets, or anything metal in a greenhouse. Water and electricity are both abundant. If you touch with both hands, the electric charge can pass across your heart. You could be electrocuted.

14. Danger! This Cord is Beyond Repair!
Discard immediately!

15. Note: Taping a cord like this is not permitted.
This cord would be dangerous to use. Discard immediately.

16. 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!

17. 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.

18. GFCIs Portable GFCIs are common in landscaping
All extension cords must have a GFCI connected to them, including those running off of a generator.
Testing a GFCI:
Test the GFCI monthly. First plug a lamp into the portable GFCI (the light should be turned on), then press the "TEST" button on the GFCI. If the GFCI is working properly, the light should go out. If not, have the GFCI repaired or replaced. Reset the GFCI to restore power. If the "RESET" button pops out but the light does not go out, the GFCI has been improperly wired and does not offer shock protection. Replace the portable GFCI.

19. Additional Information
OSH Answers: Electrical Safety - Basic Information
OSH Answers: Electric Tools - Basic Safety

20. Call Before You Dig
Failure to contact and locate utilities can lead to catastrophic events and large repair bills.

21. 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 protected from damage.

22. 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

23. Power Line Clearance Distance from Power Lines 10 feet Voltages
< 50 kV
200 kV
350 kV
500 kV
650 kV
800 kV
Power Line Clearance:
Table shows how clearance distances change when the voltage is greater than 50 kV.
The highest voltage line in the country, 765,000 V, is owned by Commonwealth Edison. Commonwealth Edison is located in the Northeastern Illinois.

24. Voltage range (volts) (phase to phase) Minimum working distance
Minimum Working Distances from Energized Conductors for Line-Clearance Tree-Trimmers
Voltage range (volts) (phase to phase)
Minimum working distance
2,100-15,000
2 ft, 0 in.
15,100-35,000
2 ft, 4 in.
35,100-46,000
2 ft, 6 in.
46,100-72,500
3 ft, 0 in.
72, ,000
3 ft, 4 in.
138, ,000
3 ft, 6 in.
161, ,000
3 ft, 8 in.
230, ,000
5 ft, 0 in.
345, ,000
7 ft, 0 in.
500, ,000
11 ft, 0 in.
700, ,000
15 ft, 0 in.
Table 1.--Minimum working distances from energized conductors for line-clearance tree trimmers and line-clearance tree-trimmer trainees as established by 29 CFR (q)(2)(iv), Table R-3

25. 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.

26. 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

27. Additional Information
OSHA Construction eTool: Electrical Incidents
Face report -

28. Material Handling and Storage
A common problem on sites is insufficient space for storage. This frequently makes the area under power lines tempting locations for staging landscaping materials. Such areas are frequently along right of ways and site access routes. It should be no surprise that most studies of power line accidents conclude that these locations pose the greatest risk.
Avoid Storing Materials Under
Power Lines

29. 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.

30. 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.
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. Workers should check for overhead power lines before doing any work. Plan your route of travel to avoid power lines.

31. 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.

32. 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.