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[2] APPLICATIONS AND FEATURES
2-1 Applications
This instrument is a DC insulation resistance tester
designed to measure insulation resistance of electric lines
and electric equipments in the range of the CAT. III 300 V
and CAT. II 600 V.
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Measurement categories (overvoltage categories)
The IEC (International Electrotechnical Commission)
standard categorizes measuring circuits for safe use
of measuring instruments in low-voltage facilities. The
categorization includes II, III, and IV. Higher number
of the category corresponds to the place with higher
transient energy. For safe measurement, wear insulating
gloves, dust-proof glasses and so on in the place of
CAT. III.
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Measurement category IV (CAT. IV)
Applicable to measurements performed at the source of
the low-voltage mains installation.
Applicable to measurements performed in the buildings
such as electric measurements on the ripple control units
and transient overcurrent protection devices.
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Measurement category III (CAT. III)
Applicable to measurements performed at the low-
voltage mains installation in the buildings.
Applicable to measurements on distribution boards,
circuit-breakers, wiring including cables, bus-bars,
junction boxes, switches, socket-outlets in the fixed
installation, and equipment for industrial use and
some other equipment such as stationary motors with
permanent connection to the fixed installation.
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Measurement category II (CAT. II)
Applicable to measurements on circuits directly
connected to utilization points of the low-voltage mains
installation.
Applicable to measurements on household appliances,
portable tools, and similar equipment.
Voltages used in the measurement categories are based
on line-to-neutral voltage. The secondary side of 480 V
of Three-phase four-wire systems with earthed neutral or
Three-phase three-wire systems unearthed is categorized
into CAT. III 300 V.
2-2 Features
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Safety design that conforms to the IEC61010/IEC61557
• Though it is pocket size, when measuring MΩ, the rated
current is more than 1 mA.
• Provides 7 test voltages (15/25/50/100/125/250/500 V),
and any voltage can be selected and fixed. The feature
prevents you from mistakenly selecting 500 V.
• Automatically-held readings after measuring MΩ
The LED level meter shows the reading.
•
Easy-to-read LCD with the fixed decimal point
•
The lighting lamp illuminates a place to be measured,
and the LCD has a backlight.
•
All-in-one body with the probe enables you to easily
watch the tip of the probe and the display at once.
•
Provides the probe that enables you to measure through
a hole of a circuit breaker cover.
• Auto Power Off feature (approx. 10 min.)
•
Auto-discharge feature
•
When the probe is applied to the object which is a live-
wire (over 30 V) before pressing the test button in the
MΩ function, the instrument automatically detects it
and displays the voltage, and will not generate any test
voltage.
Integrating wattmeter
Service wire
Service entrance
Interior wiring
Wall socket
Wall socket
Distribution board
CAT .
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CAT .
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CAT .
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