Hioki 3256-50, Instruction Manual

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5
Measurement categories
(Overvoltage categories)
This product complies with CATIII (600 V), CATII (1000 V) safety
requirements.
To ensure safe operation of measurement products, IEC 61010
establishes safety standards for various electrical environments,
categorized as CAT I to CAT IV, and called measurement cate-
gories. These are defined as follows.
Higher-numbered categories correspond to electrical environ-
ments 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.
Using a measurement product in an environment designated
with a higher-numbered category than that for which the product
is rated could result in a severe accident, and must be carefully
avoided.
Never use a CAT I measuring product in CAT II, III, or IV envi-
ronments.
The measurement categories comply with the Overvoltage Cate-
gories of the IEC60664 Standards.
CAT I
Secondary electrical circuits connected to an AC elec-
trical outlet through a transformer or similar device.
CAT II
Primary electrical circuits in equipment connected to
an AC electrical outlet by a power cord (portable tools,
household appliances, etc.)
CAT III
Primary electrical circuits of heavy equipment (fixed
installations) connected directly to the distribution
panel, and feeders from the distribution panel to out-
lets.
CAT IV
The circuit from the service drop to the service en-
trance, and to the power meter and primary overcur-
rent protection device (distribution panel).