Electrical safety

1. ELECTRICAL SAFETY

2. Hazards of Electricity
• Direct Contact with current (Electric shock,
internal burns)
• Without current flow through body (flash
over burns, radiation burns)
• Fire and explosion (electrical ignition,
static Electricity)

3. Human Resistance to Electric
Current
Human Resistance to Electric Current:
Body Area/Condition Resistance in Ohms
Dry Skin 1,00,000 to 6,00,000
Wet Skin 1000
Internal Body (Hand to Foot) 400 to 600
Ear to Ear About 100

4. Effects of current on Humans’ Body
Type of Current
Effect
AC 50Hz DC AC 10000 Hz
0-1 mA 0-5 mA 0-9 mA No Sensation
1-8 mA 6-55 mA 10-55 mA Mild Shock
9-15 mA 60-80 mA 60-80 mA Painful Shock
16-20 mA 80-100 mA 80-100 mA Some Loss of Muscle control
20-45 mA 100-350 mA
Sever shock and loss of muscle
control
50-100 mA 400-800 mA Possible Heart failure
Over 100
mA Over 800 mA Usually Fatal

5. Severity of Electric shock
• Amount of electric current
• Duration of current flow
• Path of electric current flow

7. Ohms Law

8. Ohms Law
Clothing should fit snugly to
avoid danger of
becoming entangled in
moving machinery or
creating a tripping or
stumbling hazard
Resistance can be added to the
body through the use of
insulated tools, gloves, boots,
and other gear

9. Using Portable Electric-Powered Tools Safely
Before you use a tool :
• Verify that it bears an electrical test label to indicate it successfully
passed inspection and tests for electrical safety within the previous
six months.
• Know the application, limitation, and potential hazards of the tool.
Operate according to the manufacturer's instructions.
• Inspect the cord for the proper type. Electric-powered tools must
either have a three-wire cord with ground or be double insulated.
Never use a plug that has its ground prong removed.
• Inspect the tool for frayed cords, loose or broken switches, and
other obvious problems. Tools that fail this inspection must not be
used. These must be removed from service and labeled "Do Not
Use" until repairs are made.

10. Using Portable Electric-Powered Tools Safely
When using the tool:
• Do not use electric-powered tools in damp or wet locations.
• Keep guards in place, in working order, and properly adjusted.
Safety guards must never be removed when the tool is being used
• Avoid accidental starting. Do not hold a finger on the switch button
while carrying a plugged-in tool.
• Safety switches must be kept in working order and must not be
modified. If you feel it necessary to modify a safety switch for a job
you're doing, use another tool.
• Work areas should have adequate lighting and be free of clutter.

11. Using Portable Electric-Powered Tools Safely
Servicing and storing tools:
• Never modify a tool to use for a job it's not
intended to do.
• Disconnect power tools while servicing or
storing.
• Do not wrap the cord around the tool for storage.
• Store tools in a dry place.

12. How electrical safety is ensured in Refinery
Construction ?
Electricity and Worker Safety
• Engineering of Construction Power Network
• Selection of proper equipments & proper tools for different
classified area
• Validation of all electrical installation by "Qualified Person".

13. How electrical safety is ensured in Refinery Construction ?
Energized Equipment :
• The "Qualified Person" (as defined by OSHA) is only
authorized
• Making Circuits Safe
• Lock-out and Tag-out Procedures
• Voltage Sensors and Meters
• Specific Electrical Lock-out Requirements
• Key Interlocking Systems
• Grounds and Grounding
- System, Equipment and Static Grounds
- Ground Fault Interrupters (ELCB) and Relays (GFR)

14. How electrical safety is ensured in Refinery Construction ?
Safe Work Practices :
• Safe Approach Distances
• Alertness
• Illumination Requirements
• Conductive Apparel and Insulated Tools
• Employing Protective Shields
• Portable Ladders Around an Electrical Hazard
• Confined or Enclosed Work Spaces
• Properly Dealing with Interlocks

15. How electrical safety is ensured in Manufacturing area ?
Use of Equipment:
• Portable Electric Equipment and Cords
• Electric Power and Lighting Circuits
• Test Instruments and Equipment
• Use of Flammable Materials- Extinguishing Electrical
Fires
• Explosion Proof & Dust Ignition Proof Applications

16. How electrical safety is ensured in Construction ?
Personnel Protection :
• Personal Protective Equipment
• Safety Signs, Tags, and Barricades
• Danger vs. Caution vs. Warning