Hioki Memory HiLogger LR8401-20 Instruction Manual page 17

Measurement categories
To ensure safe operation of measuring instruments, IEC 61010 establishes safety stan-
dards for various electrical environments, categorized as CAT II to CAT IV, and called
measurement categories.
• Using a measuring HiLogger in an environment designated with a
higher-numbered category than that for which the HiLogger is rated
could result in a severe accident, and must be carefully avoided.
• Never use a measuring HiLogger that lacks category labeling in a
CAT II to CAT IV measurement environment. Doing so could result
in a serious accident.
This HiLogger conforms to the safety requirements for CAT II (300 VAC,DC) measuring
instruments.
CAT II: When directly measuring the electrical outlet receptacles of the primary electrical
circuits in equipment connected to an AC electrical outlet by a power cord
(portable tools, household appliances, etc.).
CAT III: When measuring the primary electrical circuits of heavy equipment (fixed
installations) connected directly to the distribution panel, and feeders from the
distribution panel to outlets.
CAT IV: When measuring the circuit from the service drop to the service entrance, and to
the power meter and primary overcurrent protection device (distribution panel).
Difference between "Measurement" and "Recording"
The measurement and recording processes are distinguished as follows for the purposes
of these instructions.
Measurement: The acquisition of input values into internal HiLogger memory or to a PC via
communications.
Recording : Storing measurement data on a CF card, USB flash drive or on a PC via data
communication.
Measured data (data acquired in internal memory) is erased whenever a new measure-
ment starts. To retain data, always record (save) it.
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Safety Information