KYORITSU 2009A - Manual (Page 5)

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CAUTION
● Make sure that the function selector switch is set to an appropriate
position before making measurement.
● Always make sure to insert each plug of the test leads fully into the
appropriate terminal on the instrument.
● Make sure to remove the test leads from the instrument before
making current measurement.
● Do not expose the instrument to the direct sun, extreme temperatures
or dew fall.
● Be sure to set the function selector switch to the “OFF" position
after use. When the instrument will not be in use for a long period
of time, place it in storage after removing the battery.
● Use a damp cloth and detergent for cleaning the instrument. Do
not use abrasives or solvents.
○ Measurement categories (Over-voltage categories)
To ensure safe operation of measuring instruments, IEC61010
establishes safety standards for various electrical environments,
categorized as CATⅠ to CATⅣ, and called measurement
categories. Higher-numbered categories correspond to electrical
environments with greater momentary energy, so a measuring
instrument designed for CATⅢ environments can endure greater
momentary energy than one designed for CATⅡ.
CAT Ⅰ : Secondary electrical circuits connected to an AC electrical
outlet through a transformer or similar device.
CAT Ⅱ : Primary electrical circuits of equipment connected to an
AC electrical outlet by a power cord.
CAT Ⅲ : Primary electrical circuits of the equipment connected
directly to the distribution panel, and feeders from the
distribution panel to outlets.
CAT Ⅳ :The circuit from the service drop to the service entrance,
and to the power meter and primary over-current
protection device (distribution panel).
Incoming wire
CAT.IV
Interior wiring
Transformer
CAT.I
CAT.II
CAT.III
Socket