1. Electrical

2. Serious Exposure
Electrocution is one of the top four causes of construction fatalities
Nearly half of those fatalities were the result of contact with overhead power lines
OSHA is focusing more attention to these exposures

3. Applicable Standards
Electrical standards are among the most frequently cited by OSHA
No Lock Out/Tag Out
Improper Wiring Methods
Inadequate Components and Equipment
OSHA references the following for guidelines
Electric Safety Requirements for Employee Workplaces and codes (NFPA 70E)

4. Basic Terminology
Conductor – A material that has very low resistance to the flow of electric current
Insulator – Material that resists electric current
Grounding – A low resistance path to the earth for electric current
Amps – The amount of electricity flowing
Volts – The force at which the power flows

5. Grounding Service Ground – Protects machinery/equipment
Equipment Ground – Protects worker from tool malfunction
2 options for safe grounding:
Assured Grounding Program
Written Program
Testing (continuity and terminal connection)
Test Schedule
Completed by Competent person
GFCI (Ground Fault Circuit Interruption)

6. Ground Fault Circuit Interruption
Must be provided for all 120v single phase 15 and 20 amp circuits that are not part of the permanent wiring
Permanent wiring using an extension cord is considered temporary power and requires a GFCI
All temporary power sources must have GFCI protection either at main box, extension cord, or tool.

7. Ground Fault Circuit Interruption
Ground Fault Circuit Interrupters (GFCI’s) sense changes in current (5 milliamps) and stop energy flow.
Devices stop current in 1/40 of a second
Never bypass any protective system or device designed to keep you from contact with electrical current.

8. Electric Shock Body becomes part of the electrical current
Current enters the body at one point and leaves at another (path to ground)
Shocks can occur when a person contacts:
Both wires
Wire to ground
Any conductor that is energized

9. Physical Effects
Amps are the true measure of current absorbed, not volts
We are good conductors, the human body is 70% water
Involuntary muscle contraction is the reason we are affected
Can’t let go of energized object
Breathing is impaired
Heart rhythm is disrupted

10. Physical Effects 1 mA 16 mA 20 mA 100 mA 2 amps 15 to 20 amps
Barely perceptible Max current an average man can grasp and let go Paralysis of respiratory muscles Ventricular fibrillation threshold Cardiac standstill and internal organ damage Current required to trip common household breaker

11. Influencing Factors of a Shock
Circumstances that affect the outcome of an electric shock;
Circuit voltage
The bodies external (skin) and internal resistance
Total current flowing through the body
Current path
The duration of the shock

12. Employer Responsibilities
Equipment must be:
Free from recognized hazards
Suitable and identified through listing, labeling, or certification of purpose.
Designed with adequate mechanical strength and durability
Other items for consideration
Electrical insulation
Heating effects /conditions of use
Arcing effects
Use classifications

13. Guarding
Live parts of electrical equipment operating at 50 volts or more must be guarded against accidental contact.
Means of acceptable guarding include:
Isolation in a cabinet, room, or vault accessible only by qualified persons
Use of partitions or screens to exclude unqualified persons
Elevation of eight feet or more above the floor
Electric installations over 600 require special protection
metal-enclosed
Vault
controlled by lock

14. Lock Out / Tag Out LOTO written program Components
Documented energy control procedures
Employee Training program
Inspection program

15. Lock Out / Tag Out
Purpose is to draw attention to and disable a live energy source during service and repair work.
Lock Out physically disables the energy source, Tag Out provides a warning only
Only the employee who placed the lock or tag may remove it!

16. Safe Power Shutdown - 5 Steps -
Preparation and Notification– Understanding energy source and alerting all affected employees
Shutdown – De-energizing procedure
Isolation – Properly locking all power sources
Lock & Tag Application
Color coding for different trades
Employee assigned locks
Photo tags, helps locate employee, makes association
Control and Verification– Control stored and residual energy with locks in place

17. Re-energizing - 3 Steps -
Inspection – checking the work area and surrounding machinery and for employees
Notification – Make notice to all affected employees as to what will be re-energized
Removal of Tags and Locks

18. Tags and Locks Tags and Locks must be:
Durable – resist conditions of environment
Standardized – color code and format
Substantial – strong enough to minimize false removal
Identifiable – clear message, know who it is protecting

19. Extension Cords
Cords with missing ground prongs, broken insulation, crimping or crushing must be removed from service.
Splicing is prohibited but new end can be installed
Unplug at the receptacle
Any cord that has to cross a pthway must be protected
OSHA considers an extension cord temporary power, no matter the power source!
Service Ratings
Hard Service
(types S, ST, SO, STO)
Junior Hard Service
(types SJ, SJO, SJT, SJTO)
Home use, small appliance
(type SP)

20. Portable Generators
Never use a generator indoors or in an attached garage.
Use extension cords with adequate duty ratings.
To prevent electrical shock, make sure your generator is properly grounded.
Do not store fuel indoors or try to refuel a generator while it's running.
Turn off all equipment powered by the generator before shutting it down.

21. Other Considerations
Environmental Deterioration of Equipment - Unless specified for use in such an environment, no conductors or equipment should be exposed to;
Damp or wet locations
Gases, fumes, vapors, liquids, or other deteriorating agents
Excessive Temperatures

22. Electrical Checklist Extension cords: - No crimping or crushing
- No missing insulation
- No signs of stress at plug
All extension cords out of high traffic areas:
- Road ways (protective cover)
- Driveways
- Hallway, entrance, stairwell
Lock Out / Tag Out plan for all maintenance operations
Equipment rated for duty and environment
Proper PPE when necessary
GFCI protection at box, cord, or tool
Awareness of all overhead power lines
All tools double insulated
Pre-job identification of all underground utilities
Generators must have earth ground