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