Indirect contact results from contact with exposed conductive part such
as the metal structure piece equipment that has become live a
result fault.
. 6. The Regulations call this basic protection. 6. The Regulations call this fault protection. The shock current causes unnatural operation
of the muscles and the result may that the person unable release
the live conductor causing the shock, the person may thrown across
the room.7 this book.
If the body becomes part more powerful external circuit, such the
electrical mains, and current flows through it, the body’s normal electrical
operations are disrupted.
Two types contact will result person receiving electric shock. Protection can also provided fixed obstacles
such guardrail around open switchboard placing live parts out
of reach with overhead lines.
Basic protection and fault protection
The human body’s movements are controlled the nervous system.7 of
this book.
In installations operating normal mains voltage, the primary method of
protection against direct contact insulation. Very
tiny electrical signals travel between the central nervous system and the
muscles, stimulating operation the muscles, which enable walk,
talk and run and remember that the heart also muscle.Overcurrent, short circuit and earth fault protection
235
Protective equipotential bonding this equipotential bonding for the
purpose safety shown Fig.
Other methods basic protection include the provision barriers or
enclosures which can only opened the use tool, when the sup-
ply first disconnected. All live parts are enclosed
in insulating material such rubber plastic, which prevents contact
with those parts. The insulating material must, course, suitable for
the circumstances which they will used and the stresses which
they will subjected.2.1).
Try This
Definitions
● help you remember these definitions
try writing them out your own words
● just identify the essential words. The IEE Regulations call this basic protection (IEE
Regulation 131.
Definition
Protective equipotential bonding this
is equipotential bonding for the pur-
pose safety shown Fig. The current which flows through the body determined the
resistance the human body and the surface resistance the skin the
hands and feet.
This leads the consideration exceptional precautions where people
with wet skin wet surfaces are involved, and the need for special consid-
eration bathroom installations.
Direct contact with live parts which involves touching terminal line
conductor that actually live
