Page 88 - Electrical Safety of Low Voltage Systems

CHAPTER5

Effects of Electric

Currents Passing

Through the Human

Body, and Safety

Requirements

When reason and unreason come into contact,
an electrical shock occurs.
friedrich von schlegel (1772–1829)

5.1 Introduction
It has been discussed in Chap. 4 that the earth, due to its conductive
nature, can be an available return path to ground currents and, there-
fore, allows circulation of current through the person in contact with
an energized object. Current passing through a human body, upon
touch of an energized object, cause electric shock, also referred to as
macroshock.
Electric currents are harmful to human beings primarily in view
of the fact that they interfere with the biological electrical activity
of the body. This interference disrupts the proper natural electrical
pattern in the organism and can cause lethal consequences, even in the
absence of other effects, such as burns. Currents, in fact, also increase
the temperature of body tissues due to the Joule effect. In some cases,
temperatures may rise up to 3000 C.
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