Safety at Electrical

1. Electrical Hazards
HEALTH AND SAFETY PRESENTATION

2. Electrical Hazard
• Definition
• A dangerous condition in which a person may sustain an
injury by making an electrical contact with an energized
equipment.
•Electrocution
• It occurs when a person makes a contact with a conductor
carrying a current and simultaneously contacts the ground or
another object that includes a conductive
path to the ground

3. Sources of Electrical Hazards
• Equipment failure
• Improper insulation
• Environmental conditions
• Electrostatic hazards
• Arc and spark hazards
• Combustible and explosive hazards

4. Electrical Hazards (Continued)
• Equipment failure
• Short circuit are produced
•Reasons
• Improper insulations
• Temporary insulations
• Reversed polarity are being used

5. Electrical Hazards (Continued)
• Improper insulations
• Contact with a bare wire
• Reasons:
• Direct sunlight or other sources of ultraviolet
light
• Repeated exposure to elevated temperatures
• Animals such as rodents or insects chewing or
eating the insulation material
• Moisture and humidity being absorbed by the
insulation material

6. Electrical Hazards(Continued)
• Environmental conditions
• Water
• Resistance of wet body is 450 ohms
• Dry body is 600, 000
• Lighting strikes
• A single bolt of lightening contains 100
million volts

7. Electrical Hazards (Continued)
• Electrostatic
• Briskly rubbing a nonconductive material over a stationary surface
• Vehicle tires rolling across a road surface
• Friction between a flowing liquid and a solid surface
• Arc and spark hazards
• contact of conductors to complete a circuit, an
electric arc
• Combustible and explosive hazards
• High currents through contaminated liquids may cause the contaminants to
expand rapidly and explode
• circuit breakers or transformers

8. Electrical Hazards to Humans
• Electric shock is due to current flow
• Skin resistance ranges from 450 ohms to 600,000 ohms, depending on skin moisture
• Levels of current:
• Freeze:
• Let-go Current:
• Severity depends on the dosage of current, (see table on next slide)
• Current paths through hear, brain or trunk are generally more injurious than paths through
extremities

9. Current effects on
Human Body (60 Hz)

10. Detection of Electrical Hazards
Circuit Tester: A test equipment with two wire leads capped by probes and connected to a small
bulb. (Range:110-220volts)
Receptacle Wiring Tester: A device with two standard probes for checking electrical current
Continuity Tester: A device to check whether a conductor is properly grounded or has a break in
the circuit.

11. Reduction of Electrical Hazards
• Electrical System Grounding: Equipment is connected to earth through metal wire
• Separate Equipment Grounding: All the metal parts of an equipment are grounded.
• Ground Fall Interrupter: A device which detect open ground circuit and therefore interrupts the
flow of current
• Humidification: It reduces the electrical static charge storage
• Antistatic Materials: Increases surface conductivity and absorb moisture, which reduces
resistance and the tendency to accumulate charges.
• Ionizers and Electrostatic Neutralizers: Ionize the air to provide a conductive path for the flow
of charges
• Radioactive Neutralizers: Consist of radioactive element which emits positive charges to
neutralize negative charge

12. Reduction of Electrical Hazards (Continued)
• Fuses: Breaks the circuit when current flow increases certain limit
• Magnetic Circuit Breaker: Consist of solenoid which acts as magnet. It also breaks circuit when
current increases a certain limit.
• Thermal Circuit Breaker: Excess current produce heat, thermal circuit breaker detects the heat
and breaks the circuit
• Double Insulation: Apply 2nd level insulation in addition to standard insulation
• Interlocks: Interlocks automatically breaks high voltage circuits in unsafe situation
• Warning Devices: To alert the personnel about detected electrical hazard.

13. OSHA’S Electrical Standards
• OSHA” Stands for the Occupational Safety and Health Administration of the United States
Department of Labor.
• Two categories of standards:
 Design of electrical systems Safety-Related Work Practices
Code Purposes Code Purposes
1910.302 Electric utilization systems 1910.331 Scope
1910.303 General requirements 1910.332 Training
1910.304 Wiring design and protection 1910.333 Selection and use of work practices
1910.307 Hazardous (classified) locations 1910.334 Use of equipment
1910.308 Special systems 1910.335 Safeguards for personal protection

14. Electrical Safety Program
• In United States electrocution accounts for almost 6 percent of all workplace deaths, So an
effective electrical safety program has to be implemented
Strategies:
Following strategies for establishing electrical safety program:
1. Develop and implement a comprehensive safety program.
2. Revise existing programs.
3. Ensure compliance with existing OSHA, the NEC and the National Electrical Safety Code
4. Provide adequate training for
Identification of hazard Control of hazard Specialized training for workers near to electrical components

15. Electrical Safety Program (Continued)
• In United States electrocution accounts for almost 6 percent of all workplace deaths, So an
effective electrical safety program has to be implemented
Strategies:
Following strategies for establishing electrical safety program:
1. Develop and implement a comprehensive safety program.
2. Revise existing programs.
3. Ensure compliance with existing OSHA, the NEC and the National Electrical Safety Code.
4. Provide adequate training for
Identification of hazard Control of hazard Specialized training for workers near to electrical components

16. Electrical Safety Program
Strategies:
5. Conduct safety meetings regularly.
6. Conduct scheduled and unscheduled safety inspections at work sites.
7. Encourage all workers to participate in workplace safety.
8. Conduct job hazard analyses to identify potential electrical hazards and safety interventions.

17. ELECTRICAL HAZARDS SELF-
ASSESSMENT

18.  One of the best strategies for safety personnel is to ask for assistance of supervisors.
 To help prevent accidents and injuries from electrical hazards, safety personnel should consider developing
checklists supervisors can use to undertake periodic self-assessments in their areas of responsibility.
 The checklist may include all the questions necessary and required to maintain a safe environment for the
workers. E.g.
1. Are all portable electric tools and appliances grounded or double insulated?
2. Are all ground connections clean and tightly made
3. Are bearings in all electrical motors in good condition?
4. Are all portable lights equipped with the proper guards?

19. PREVENTION OF ARC FLASH INJURIES

20.  An arc flash is an electrical short-circuit that travels through the air
Rather than flowing through conductors, bus bars, and other types of equipment.
 The uncontrolled energy released by an arc flash can produce high levels of heat and pressure. It can also cause equipment to
explode, sending dangerous shrapnel flying through the air.
 Electrical equipment malfunctions
 A person working near a piece of energized electrical equipment might accidentally
drop a tool that then makes contact with an electrical circuit or conductor. The result
is an arc flash that can injure or even kill the worker and cause equipment damage.
 wearing flammable clothing instead of appropriate PPE.
 Ignite clothing, cause severe burns, and even damage hearing (High pressure)
 The best way to prevent arc flash injuries is to de-energize the electrical equipment in question and lock or tag it out before
beginning maintenance.
 Some maintenance and service functions such as troubleshooting require that the equipment being worked on be energized.
When this is the case, it is important to consult the NFPA’s Handbook for Electrical Safety in the Workplace.

21. 1. Perform a flash hazard analysis in accordance with NFPA 70E.
2. Establish a flash protection boundary around the equipment in question in accordance
with NFPA 70E.
3. Select the PPE that will be worn by the workers who will perform the tasks in
question on the energized equipment.

22. TRAINING REQUIREMENTS FOR
WORKERS

23.  The training requirements for workers who face the risk of electric shock that is not reduced to a safe level are clarified in
OSHA CFR 1910.332. The standard’s requirements apply to the
following classifications of workers:
1. Blue-collar supervisors
2. Electrical and electronic engineers
3. Electrical and electronic equipment assemblers
4. Electrical and electronic technicians
5. Electricians
6. Industrial machine operators
7. Material handling equipment operators
8. Mechanics and repairers
9. Painters
10. Riggers and roustabouts
11. Stationary engineers
12. Welders

24. The actual training requirements are as follows:
1. Skills and techniques necessary to distinguish exposed live parts from other parts of electric
equipment.
2. Skills and techniques necessary to determine the nominal voltage of exposed live parts.
3. Clearance distances and corresponding voltages to which they will be exposed