1) Electrocutions can occur from a variety of voltages including domestic, industrial, and lightning sources. Fatal electrocutions are divided based on voltage into domestic (220-240V), industrial (high voltages), and lightning. 2) The factors that determine the effects of electrocution include voltage, amperage, current type (AC vs. DC), duration of contact, resistance of body tissues, area of body contact, and path of current through the body. 3) Death from electrocution is usually caused by ventricular fibrillation leading to cardiac arrest, but can also result from spasms of the respiratory muscles or paralysis of the respiratory center in the brain.

1. ELECTROCUTION
The passage of electric current through the body is capable of
producing wide range of effects, varying from insignificant
localized muscular spasm with little or no contact burns to
instantaneous death with little or no burns or extremely
severe burning.
FATAL ELECTROCUTION IS DIVIDED INTO THREE GROUPS (ACC.
TO VOLTAGE)
1) Domestic- the voltage of domestic supply is usually 220-240
volts AC with 50 cycles per second.
2) Industrial- very high voltages are involved in driving heavy
machinery and the voltages employed by different industries
may vary.
3) Lightning flashes are also electrical discharges.

2. FACTORS INVOLVED IN ELECTROCUTION
A) FACTORS RELATED TO NATURE OF ELECTRIC
SUPPLY INCLUDE
1) VOLTAGE (TENSION)- a volt is a unit of
electromotive force. It is the force which is
required to produce 1 ampere of intensity when
passed through a conductor having resistance of
1 ohm.
LOW TENSIONS- below 50 volts are not fatal. Most
fatalities follow shock from currents at 220-240
volts which is the range of household supply.
At such voltages the usual visible damage to body
occurs in form of small electric marks and death
is due to internal derangements of functions.

3. MEDIUM VOLTAGE- i.e. under 500 volts-
predispose to prolonged contact due to
induction of spasm of muscles and therefore the
victim grips and holds on to the conductor.
Under these conditions the shock may become
lethal.
HIGH VOLTAGE- the victim may be thrown of the
source by violent muscular contractions or the
body may be extensively damaged with severe
and deep burns.

4. 2) AMPERAGE (INTENSITY)- It is the unit of electric
current and is calculated by dividing voltage by
resistance in ohms. I= V/R.
On receiving a current of 1mA, a person
experiences a tingling sensation.
At 8-20mA current- the person holds on to the
source of current.
At higher currents the person may be thrown off
the source.

5. 3) FORM OF CURRENT (WHETHER AC/DC).
An AC current is one which reverses its direction at
regular intervals. DC is one where current flows
constantly in same direction.
AC is more dangerous than DC.

6. FACTORS RELATING TO VICTIMS INCLUDE
1)RESISTANCE OF BODY TISSUES- the major
barrier to the electric current is the skin. Once
the skin has been overpowered by the electric
current, the vascular system filled with
electrolyte rich fluid serves as favorable
medium for the passage of current. Skin on
soles, finger pads and palms offer more
resistance and dry skin offers more resistance
than wet skin. Sweating reduces resistance.
Vascular areas like cheeks offer less resistance

7. 2)AREA OF CONTACT OF BODY- smaller the area of
contact between the skin and electric supply will
exert more resistance than larger area. For e.g. tip of
finger offers more resistance than palm of hand.
This may occur when one grasps a hot wire with a
wet/ sweated hand. Hence, the entire skin surface
being bathed in salt water becomes a conductor and
not enough current passes through any localized
portion of hand to generate sufficient heat to burn
the skin, hence electrocution may occur with no
visible skin burning.
Similarly electrocution may occur in bath without any
external mark.

8. SECONDLY- part/site of the body and route of
current through body has a considerable
bearing. The passage of current through the
region of heart is most dangerous.
Heart is usually involved when path is from left
arm to right leg. When head of worker may
come in contact with conductor, brain stem
may be directly involved leading to paralysis of
cardiac or respiratory centre.

9. 3)DURATION OF CONTACT- longer the contact,
greater will be the damage.
4)EARTHING/INSULATION- the current enters at
one point and then leaves the body at some
exit point, usually to earth. The better the
contact between the person and the earth at
the time of sustaining electric shock the more
dangerous will be its effects.
A person standing with dry shoes on a dry
surface may rarely notice a shock which could
prove fatal to some one standing bare foot on
a wet surface.

10. MECHANISM OF DEATH
1) VENTRICULAR FIBRILLATION- most deaths from
electric shock are due to cardiac arrythimas
usually venticular fibrillation terminating in
arrest. (abnormal electrical activity in heart
causes uncoordinated contraction of muscles of
ventricles).
2)SPASM OF RESPIRATORY MUSCLES- electric
current passing through thorax may lead to
tetanic contraction (muscular contraction without
relaxation) of muscles of respiration and
ultimately produces respiratory arrest.

11. 3)PARALYSIS OF RESPIRATORY CENTRE- it occurs
when current passes through head
4)SECONDARY CAUSES- death may occur due to
sustaining of mechanical injuries. It may
happen when a worker working on a high
voltage supply system gets electrocuted and
falls from a height and receives head injury or
some other injuries.

12. AUTOPSY FINDINGS
FINDINGS IN DEATH DUE TO LOW OR MEDIUM
TENSION CURRENTS- the point where the
current enters the body is characterized by
presence of electric mark or electric burn
(JOULE BURN OR ENDOGENOUS BURN). Fatal
electrocution can occur without any visible
marks (deaths occurring in bath tubs).

13. SOME IMP FEATURES OF MARK INCLUDES
1)If the contact of skin with conductor is good
and firm, the passage of current heats up
tissue fluid and the skin offering resistance
gets split and blister may be raised.
2)The blister may get ruptured if the contact is
for long period.

14. • 3) If the contact is not good the current jumps
the gap in form of a spark between the source
and skin and causes outer skin keratin to melt
over a small area. On cooling the keratin gets
condensed into hard brown nodule and this is
termed as ‘SPARK LESION’.
• A well developed electric mark is round or
oval shallow crater , bordered by raised areola
of pale skin around apart or whole of its
circumference. The floor of crater is lined by
pale flattened skin and ridge pattern may or
may not be preserved.

15. These electric marks are produced by conversion
of electricity into heat within tissues and
therefore they are termed as endogenous
burns.
EXIT MARK- they are seen as split in the skin or
sometimes even lacerations. Burns and
perforations of clothings or shoes may be seen
over the sight of exit. If the current enters and
leaves the body at a wide area of low
resistance (wet hand/ wet body) no marks are
seen.

16. FINDINGS IN DEATHS DUE TO HIGH TENSION
CURRENTS- (Exogenous burns)
Injury occurs either by direct contact or by
indirect results arching or flash over.
The high tension injuries are usually seen in
lineman working on grid system and
occasionally in thieves stealing wires from
high voltage over head lines.

17. In high voltages the current may spread to a few
cm distance and the person may be knocked
down without coming in contact with the
source.
There may be charring of tissues but depending
on the degree they may be
1)Brownish discoloration of large areas of skin
apart from actual burning.
2)Arborescent pattern resembling lightning
burns.
3) Crocodile skin effect comprising of confluent
multiple spark burns over large areas of body.

18. INTERNAL FINDINGS- gross findings in internal
organs may be absent because the tissues are
mainly aqueous and contain electrolytes for
the passage of current. Mostly death is due to
cardiac arrythimas leading to venticular
fibrillation and arrest.
If death is due to spasm of respiratory muscles-
cyanosis of face, petechial haemorrhages in
skin of face and beneath pleura and
epicardium, congestion of viscera and oedema
of lungs.
Suspended animation is common in
electrocution.

19. MEDICOLEGAL IMPORTANCE
MOSTLY ACCIDENTAL.
SUICIDAL AND HOMICIDAL RARE.

20. LIGHTNING
In lightning the discharge may be from cloud to
cloud or from cloud to earth through some
object usually the tallest in contact with the
earth. Lightning chooses the easiest path (not
the shortest)i.e. path of least resistance.
The electric current is direct of about 20,000 A
and a million volts operating over an average
period of 30 sec.

21. The effects of lightning are due to
Passage of very high potential electricity which
liberates tremendous amount of energy in
form of heat and the burns are superficial
owing to short duration of flash.

22. Lightning produces
1) Surface burns –which are tissue burns and
usually travel through metallic objects carried
or worn by the victim.
2) Arborescent burns or filigree burns or
feathering which appears like branches of a
tree. These are due to rupture of small blood
vessels at several places.
3) Blast effects- may be observed in form of
tearing of clothings or shoes or effects may
also be seen on trees showing areas of
scorched leaves and vegetation.

23. DIAGNOSIS OF DEATH
May be achieved by considering the following
1) History of thunderstorm in the locality
2) Evidence of effects of lightning in the vicinity of
scene of death i.e. damage to trees, houses or
animals.
3) Tearing of clothings.
4) Characterstic nature and distribution of burns which
are superficial due to brief duration of flash.
5) Sudden death may occur due to involvement of CNS
causing paralysis of cardiac or respiratory centre.

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