Page 40 - FL-20A Instruction Manual
Model FL-20A Cable Fault Locator
skin tissue. This limit becomes important at frequencies over
several kHz, because limits addressing other hazards would
not automatically prevent burns.
There are a number of commonly used techniques to
reduce the risk of electric shock. Each has attributes that
render it more effective for certain applications. In some
cases, a combination of techniques may be the best method
to reduce the risk of electric shock to an acceptable level.
The protective mechanism should be compatible with the
nature of the product, its ratings, habits and behavior of the
people using the product, and the environment in which the
product is used.
The principle of equipment grounding can be described
as follows: all accessible conductive parts are connected
together and to earth by a network of low-impedance con-
ductors to create an equipotential environment. Two impor-
tant considerations are the reliability of the connections
and the impedance of the conductors at the frequencies
involved. Ground monitors that interrupt current and/or
sound an alarm can enhance reliability. Low impedance in
the grounding conductor circuitry is important in order to
maintain low voltage to ground on accessible conductive
parts during a fault before an interrupting device shuts off
the circuit.
Double insulation enhances the reliability of the electri-
cal insulation of a product to reduce the likelihood of insu-
lation breakdown that could cause an electric shock. Each
part of a double-insulation system should be independent
and must be fully capable of acting as the sole insulation. If
one insulation fails, the other must have all of the required
attributes to prevent electric shock. It is important that the
two parts of the double-insulation system are as truly inde-
pendent as feasible. Both insulations should not be vul-
nerable to the same act (e.g., a drop on a hard surface or
immersion in water) or deteriorating agent (e.g., high tem-
perature or over-surface contamination).
Burns Cont.
Grounding
Double Insulation
