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14
Safety Notes
Measurement categories
IEC 61010 defines measurement categories to facilitate safe use of measuring instruments. Test
and measurement circuits designed to be connected to a main power supply circuit are classified
into three categories depending on the type of main power supply circuit.
DANGER
Do not use a measuring instrument to measure a main power supply
circuit whose category exceeds the instrument’s rated measurement
category.
Do not use any measuring instruments for which the rated measurement
category is not specified for measurement of main circuits.
Doing so may result in serious bodily injury or damage to the instrument or other
equipment.
Measurement category II
(CAT II)
Applicable to test and measuring circuits connected directly to utilization points
(socket outlets and similar points) of the low-voltage mains installation.
Example: Measurements on household appliances, portable tools, and similar
equipment, and on the consumer side only of socket outlets in the fixed
installation.
Measurement category III
(CAT III)
Applicable to test and measuring circuits connected to the distribution part of the
building’s low-voltage mains installation.
Example: Measurements on distribution boards (including secondary meters),
photovoltaic panels, circuit breakers, wiring, including cables, bus-bars,
junction boxes, switches, and socket outlets in a fixed installation, as
well as equipment for industrial use and some other equipment such as
stationary motors with permanent connection to the fixed installation.
Measurement category IV
(CAT IV)
Applicable to test and measuring circuits connected at the source of the building’s
low-voltage MAINS installation.
Example: Measurements on devices installed before the main fuse or circuit
breaker in the building installation.
T
Distribution panel
Service entrance
Service drop
CAT IV
Power meter
Outlet
CAT III
CAT II
Interior wiring
Fixed installation
HIOKI ST5680A961-00
Summary of Contents for ST5680
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Page 84: ...84 Individually Executing Specific Steps HIOKI ST5680A961 00 ...
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Page 154: ...154 Calibration Expiration Check Function HIOKI ST5680A961 00 ...
Page 182: ...182 Internal Circuit Configuration HIOKI ST5680A961 00 ...
Page 220: ...220 Option Specifications HIOKI ST5680A961 00 ...
Page 238: ...238 External View 16 4 External View Unit mm HIOKI ST5680A961 00 ...
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