Safe working electrical practice
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Transcript of Safe working electrical practice
Presentation by J.Majumder
Basic Electrical Safety
Be familiar with the fundamental concepts
of electrical shock.
Be familiar with the effect of electricity on
the human body.
Be able to recognize common electrical
hazards.
To flow electricity must have a complete
path.
Electricity flows through conductors,
water, metal,
The human body is a good conductor.
DEFINITION OF ELECTRIC SHOCK
Electric shock is the sensation and muscular
spasm caused when electric current passes
through the body
This is to emphasize that it is current and
NOT the voltage that causes electric shock.
No matter how much voltage is present, you will
get shock , if you will provide a ground-path for
the electric current
Current through the body
Body resistance falls with increase in
Voltage.
5000 Ohms at 24 Volts .
2000 Ohms at 250 Volts.
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Basic Electrical Safety
More than 3 ma
painful shock
More than 10 ma
muscle contraction “no-let-go” danger
More than 30 ma
lung paralysis- usually temporary
More than 50 ma
possible ventricular fib. (heart dysfunction, usually fatal)
100 ma to 4 amps
certain ventricular fibrillation, fatal
Over 4 amps
heart paralysis; severe burns. Usually caused by >600 volts
Fundamentals of Electrical HazardsFundamentals of Electrical Hazards
Fundamentals of Electrical Hazards
Hazards of Electricity
Shock/Burns/Death
To prevent
•Inspect all electrical tools and
equipment
•Frayed, cut, broken wires ,grounding
missing
Preventing Accidental Electrical Contact
Time
Prevention Electrocution
Insulate
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Basic Electrical Safety
• What is Grounding?
– Protection from electric shock
• normally a secondary protection measure
• A ground is a conductive connection
– between electrical circuit or equipment and
earth or ground plane
– creates a low resistance to the earth.
Fundamentals of Electrical
Hazards
Fundamentals of Electrical
Hazards
11
Electrical Burns
• Heating when electricity passes through the body– "Entry" and "exit" wounds caused by
electrical heating of the skin, because higher resistance of the skin results in heat generation (I2R)
• Electrical arcing (arc burns are often caused by molten metal)
• Contact with electrically heated surfaces
• Electricity-ignited firesElectrical
burns
Safety First
Insulated tools
Certified insulated gloves (1000VAC)
Safety First
Safety First
Time
Unsafe practice
Meter safety
Meters and test leads with double insulation
Meters with recessed input jacks and test leads with shrouded input
connectors
Test leads with finger guards and non slip surface
Do’s & Do not’s
Do get to know ship’s Electrical system.
Do operate equipment as per maker recommendations.
Do maintain the equipments as per maintenance procedures.
Do ensure that all guards, Covers are securely fitted after works.
Do inform before starting works.
Fill up safety forms before starting works.
All tools and measuring equipments are having t safety standard .
Do’s & Do not’s
Lock out & tag out.
Do confirm that circuits are dead.
Discharge capacitors in the circuits if
any.
Always make marking of the terminals
before removing.
Confirm everything fitted back on
completion of job
THANK
YOU