Hioki 3166 - Page 14

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Safety Notes
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DANGE
R
Indicates that incorrect operation presents an extreme hazard that
could result in serious injury or death to the user.
WARNIN
G
Indicates that incorrect operation presents a significant hazard that
could result in serious injury or death to the user.
CAUTIO
N
Indicates that incorrect operation presents a possibility of injury to
the user or damage to the product.
NOTE
Advisory items related to performance or correct operation of the
product.
The following symbols in this manual indicate the relative importance of
cautions and warnings.
Overvoltage Categories
To ensure safe use of measurement, IEC 60664 establishes safety level
standards for different locations, classified as CAT I through CAT IV, and
called overvoltage categories. These are defined as follows.
CAT
: Secondary electrical circuits that are connected to a wall outlet
through a transformer or similar device.
CAT
: Primary electrical circuits in equipment connected to a wall outlet via
a power cord (portable tools, household appliances, etc.)
CAT
: Primary electrical circuits of heavy equipment (fixed installations)
connected directly to the distribution panel, and feeders between the
distribution panel and outlets.
CAT
: The circuit from the service drop to the service entrance, then to the
power meter and to the primary overcurrent protection device.
Higher-numbered categories correspond to electrical environments with
greater momentary energy, so a measurement device designed for CAT III
environments can endure greater momentary energy than a device designed
for CAT II. Use of a lower category product in a higher category environment
could result in a severe accident and must be carefully avoided.