Hioki MR8740, Instruction Manual

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Safety Information
6
To ensure safe operation of measuring instruments, IEC 61010 establishes
safety standards for various electrical environments, categorized as CAT II to
CAT IV, called measurement categories.
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 feed-
ers 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)
Measurement categories
• Using a measuring instrument in an environment designated with a higher-
numbered category than that for which the instrument is rated could result in
severe accidents, and must be carefully avoided.
• Using a measuring instrument that has no category rating in an environment
designated with the CAT II to CAT IV category could result in severe accidents,
and must be carefully avoided.
The applicable measurement category is determined by the input module being
used. Refer to "17.6 Input Modules Specifications" (p.349).