Electrical safety1.pptx

SNTI © Copyright 1
Electrical Safety
Name of Presenter
Designation
Date

SNTI © Copyright 2
1
30
300
3000
30000

SNTI © Copyright 3
Heinrich proposed that:
 88% of workplace accidents were caused by
unsafe acts (usually by the injured
person)
 10% of workplace accidents were the result of
unsafe equipment or conditions;
 2% were unavoidable.

SNTI © Copyright 5
ELECTRICAL
SAFETY

SNTI © Copyright 6
Unsafe act
1. Adjusting, cleaning and oiling the machinery in motion
2. Operating at unsafe speed.
3. Operating without authority.
4. Making safety device inoperative

SNTI © Copyright 7
• Avoiding safety standard
• Use of faulty tools
• Lack of coordination
• Using hand instead of tools
• Follows short cut method
• Carelessness
Unsafe act

SNTI © Copyright 8
Unsafe Condition
1. Poor house keeping
2. Defective equipment/tools
3. Excessive noise levels
4. Faulty construction/ installation, like slippery, sharp edge,
rough, decayed, cracked.
5. Un safely designed machine and tools

SNTI © Copyright 9
• Inadequate Instruction
• Inadequate illumination
• Congested work area
• Improper dress
• Inadequate guarding
• Faulty electrical equipment

SNTI © Copyright 10
Danger in the use of electricity
1. Electric shock
2. Burn
3. Flash
4. Fire
5. Explosion

Electric shock
Human body is conductor of electricity. When any two parts
of the body are at different potential an electric current will
flow depending upon voltage.
Shock depends upon following : -
a) Touch Potential
b) Resistance of the parts of the body through which current is
flowing
c) Magnitude of current
d) Duration of the current flow
e) Path of current through body

ELECTRIC SHOCK: Human body is a conductor of electricity. When any two parts of the
body are at two different potentials an electric current will flow
SEVERITY OF THE SHOCK DEPENDS ON:
The Magnitude of the Current
Duration of the Current
Path of the Current Flow
Physical Condition of the Person
OTHER FACTORS:
The Voltage of the Current
Presence of moisture in the environment
The general health of the person prior to
the sock

1. Less than 1 mA No feeling
2. Up to 1 mA Barely Perceptible sensation
3. 1-2 mA Irritation current
4. 2-7 mA (Women) Vigorous muscle nerves reaction
9 mA (Men)
5. 7- 10.5 Finger muscle convulse, may not
able to relinquish grip on live conductor
9-15 mA (men)
6. 15- 20 mA Convulsion, subject freezes to conductor
Effect of current on human body

7. 20-30 mA Restriction of breathing begins
8. 30 – 50 mA May withstand current without loosing consciousness
9. 50- 250 mA Ventricular fibrillation where those signals controlling
heart operation are disorientated by more powerful
signal from other source
250 mA – 4 A Fixed convulsion , asphyxia
Effect of current on human body

Wet conditions are common during low-voltage electrocutions. Under dry
conditions, human skin is very resistant. Wet skin dramatically drops the
body's resistance.
Dry Conditions: Current = Volts/Ohms = 120/100,000 = 1mA
a barely perceptible level of current
Wet conditions: Current = Volts/Ohms = 120/1,000 = 120mA
sufficient current to cause ventricular fibrillation
If the extensor muscles are excited by the shock, the person may
be thrown away from the circuit. Often, this can result in a fall from
elevation that kills a victim even when electrocution does not.

When muscular contraction caused by stimulation does not allow the victim
to free himself from the circuit, even relatively low voltages can be extremely
dangerous, because the degree of injury increases with the length of time
the body is in the circuit. LOW VOLTAGE DOES NOT IMPLY LOW
HAZARD!
100mA for 3 seconds = 900mA for .03 seconds
in causing fibrillation
Note that a difference of less than 100 milliamperes exists between a
current that is barely perceptible and one that can kill.

SNTI © Copyright
ELECTRICAL SHOCK

SNTI © Copyright
ELECTRICAL SHOCK
Second degree burnt due to
high-voltage line
Arm with third degree burn from high-
voltage line

SNTI © Copyright
ELECTRICAL SHOCK
Electrical burn on hand and arm
Contact electrical burns. The knee on
the left was energized, and the knee on
the right was grounded

Shock Duration
Current is not the only factor in electrocution. The time factor
plays an important role. If the duration of shock is 1.0 sec or more
it will cover the entire heart cycle

DEATH DUE TO ELECTRIC SHOCK
1. VENTRICULAR FIBRILLATION:- In 80 –90 % of the fatal
cases current was found to pass through the heart. Blood circulation
ceases and brain gets affected
2. ASPHYXIA:- Shock may causes cessation of respiration . Current
passing through the body may paralyze to destroy either the nerves
or the area of the brain which controls respiration
3. TETANIC CONTRACTION OF MUSCELS:- A person might be
unable to let go of a live conductor as the current through the body
makes muscles contract. Contraction of the chest muscles could lead
to respiratory arrest

First aid and shock treatment
• Body requires circulation of blood containing oxygen
• When a victim is unconscious due to electric shock, first aid
efforts should started immediately
• Brain can live only 4 minutes without oxygenated blood.
• First check for breathing and pulse
• In case of no breathing and pulse , artificial respiration
(mouth to mouth) should be be given immediately
• First artificial respiration followed by closed chest heart
massage for 20 sec.

• The patient should be kept warm by wrapping from top to
bottom to prevent loss of body heat.
• Keep the body horizontal position with feet 12 –13 inches than
the head.
• Keep the patient in the recovery position
• Attempt to stop any flow of blood.
• Remove false teeth and foreign object
• Do not block the air passage
• Loosen victim’s clothing at neck, chest and waist.
• Don’t give liquid while unconscious

1. Make sure it is safe to approach
2. Check sign of breathing
a) Open the air way by lifting the chin and feel breathing
b) Observe up down movement of abdomen
i) If the causality is breathing
Place causality in the recovery position and call medical aid
ii) If not breathing
Get someone to call medical aid while you begin mouth to
mouth ventilation

3. Mouth to mouth respiration
a) Put the person flat on the ground , face upwards
b) Open the mouth, check airways
c) Close the nostril of the causality
d) Take deep breath
e) Place your mouth over causality's mouth ensuring no leakage
f) Remove your mouth completely
g) Watch chest fall
h) Repeat this procedure

i) Check carotid pulse on the neck.
j) If still casuality is not breathing continue same at the rate
of 12 –16 times a minutes
4. If after two ventilation the casuality does not respond start
external chest compression
i) Kneel along casuality facing the chest. Place the heel of
your hand on the lower half of the breast bone to depress
chest about 4 cm. Do this 15 time at the rate of 80 a
minute
ii) Reopen the airway and give two ventilations.

Burn
When ever a short circuit or a grounding takes place due to
short circuit , a severe arc or flash takes place. If the skin is in
close proximity or contact with arc, it will suffer from burn due
to higher temperature of arc.

Class of burn
First degree:- When skin is reddened, no blistering
Second degree:- Includes reddening and blistering but does not
destroy the full thickness of skin. New skin can grow from
uninjured cells from below.
Third degree;- When full thickness of skin is destroyed in an
injury there is no chance of new skin growing

SNTI © Copyright
Rule of Nine Breakup
1. Head & Neck : 9%
2. Anterior Torso : 18%
3. Posterior Torso : 18%
4. Upper Extremities : 18%
5. Lower Extremities : 36%
6. Genitalia : 1%
35
9%
9%
18%
9%
18%
18% 18%
1%

FLASH
If a person happens to look at the arc during the short circuit
he gets a flash in the eye causing injury to the unprotected
eyes
What a burn injury can cause?
• Death
• Suffering
• Painful recovery
• Permanent scaring even after heeling
• Loss of earning capacity

What can be done about this
80 to 90% of burns are accidental and these can be avoided
by minimize:-
• By use of fire retardant clothing Cool coat
• By taking proper preventive measures at source
• By training the persons about first aid

POUR FRESH WATER ON BURN
TILL PAIN SUBSIDES

SAFETY PRECAUTIONS FOR HANDLING ELECTRICITY
1. Train your self to be safety minded. First and fore most is the
safety consciousness of operator. Always be alert and cautious
on the job. Concentrate on what you do. Think safely, act safely,
and think in time.
2. Use safety appliances provided to you, such as boots, gloves
goggles etc.
3. Expose live parts should either be properly guarded or insulated
to provide protection.

4. All switches and equipments are to be properly identified with letter
marking.
5. By identifying the danger zones and standardizing the electrical
system the electrical accidents can be minimized.
6. Where work is hazardous, at least two men shall be put to live
conductors or apparatus, at least two men shall be put to work.
However ,work should be done in hazardous area by one man only in
another man’s presence.

Nothing happens to me
since many year
Save your self
It don’t honor your
experience

7. Avoid finger ring, jewelry, metal watch, metal chains because such
article may be caught in moving parts or come in contact with
electrical circuits.
8. Wear insulated safety shoes, use rubber mat or other suitable insulated
materials when operating HT switches.
9. Rubber gloves shall be electrically tested before being used the first
time
.
10 Ground all hand electric power tools before use.

Put your leg carefully

11. Exercise extreme care when required to locate troubles in series lamp
circuits.
12. Before earthing verify that the circuit is dead with the help of tester
or a test lamp and connect the earthing leads to the earthing system
before connecting to the phases. All phases to be earthed even if work
is to be carried out in one phase. When removing earth leads they
should be disconnected from the phases first and then the earth
connection.
13. Make complete check of the circuit before applying power.

14. Make sure that all electrical equipments are adequately grounded
when installed.
15. Open or close the switch in positive manner using sufficient force to
make or break full contact of the blades quickly to prevent
unnecessary heating or arcing.
16. Discharge the capacitors before handling or making any connection.
Stored energy is sufficient to injured person coming in contact with
terminal.
17. Do not go near neutral earthing stations. Electrode might have
corroded and may give severe shock.

Avoid short cut

18. Single test lamp should not be used. Always use 3 bulb test
lamp confirming TISCO standard 02022. Wattage of all bulbs
should be the same. Testing portion cable insulation to be
removed only by 3 mm. First, test phases to ground then phase to
phase.
19. Use only all insulated hand lamps confirming to TISCO standard
02012( stock no. 211/5690) and there should not be any joint in
the cable.
20.The safety of electrical appliances and wiring is ensured in three
ways, first by insulation, second by earthing and third by
providing fuse.

21. Mark lead- covered cables with non- ferrous metal tags engrave with
an identifying number.
22. Exercise caution. Consider every circuit live. Respect all power
sources and power circuit as potentially dangerous.
23. Remove all tools and equipments upon completion of job.
24.Tie-up tags shall remain on the opened device until removed by the
workman whose name appears on the tag. In the event the workman
leaves without removing the tag , it may be removed only after
thorough investigation.

25. When it is necessary for one workman to transfer the job to
another workman and he leaves the work area for good, he shall
make sure that his successor’s tag attached to the control device
before removing his own tag.
26. Open switches fully before removing fuses. To remove a fuse
from circuit carrying field current without first opening the
switch is hazardous.
27. Use fuse puller to remove fuses.
28. Follows strictly power clearance procedure.

Your safety means your
family safety

29. Frequent blowing fuses forces the maintenance man to put
higher size fuses in the system. This results accidents, damage
to equipment.
30.Misuse of three pin plug:- don’t use three pin plugs without
top. The ground wire shall not to be interchanged. Do not insert
matchstick in the plug.
31.The metal clad switches shall always be installed in such a way
that the switch is OFF with its handle in the bottom position.
32 Tumbler switches shall always be such way that the switch is
off in top position.

33. Take electrical power clearance from an authorized person or
may be certificate holder.
34 Do not use megger in live circuit.
35. Do not use megger to discharge equipment after meggering.
Use link in neutral line.

CLASSIFICATION OF ACCIDENTS.
MINOR - Period of disablement is less than 21 days.
SERIOUS - Period of disablement is more than 20 days.
FATAL- person expires due to the injury sustained in the accident.
A - Person is unfit for more than 48 hours.
B - Person is unfit for more than 48 hours.
C - Person is fit for duty on the day of accident but the injury
Aggravates later and he becomes unfit for more than 48 hours.
D - Off job accidents – on road, latrine, bath room, canteen etc.
E - Accidents of contractor employees engaged by the departments.
F - Fatal accident of the work person.

Electrical safety1.pptx

Recommended

Recommended

More Related Content

Similar to Electrical safety1.pptx

Similar to Electrical safety1.pptx (20)

Recently uploaded

Recently uploaded (20)

Electrical safety1.pptx