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2.4 Measurement Procedure
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• Do not measure the same location with two or more
Clamp on Earth Testers at the same time. The instru-
ments will interfere with each other, preventing accu-
rate measurement.
• Verify that the [
] mark is not lit up.
When the current flowing through the grounding wire is
high (approximately 2.5 A or greater with a commercial
frequency of 50 Hz/60 Hz, approximately 100 mA or
greater with a harmonic component of 1 kHz), the cur-
rent will affect measured values, making it impossible
to measure the resistance. Check the current flowing
through the grounding wire.
* The current level at which the [
] mark lit up
depends on individual differences as well as the fre-
quency. The closer to the injected signal frequency,
the smaller the noise current that will affect opera-
tion.
• Open display
The screen will show [OPEn] if the clamp sensor is not
completely closed. Close the clamp sensor completely
and repeat the measurement.
* If an extremely large current is flowing through the
grounding wire or a DC current is superposed, the
screen may display [OPEn] even if the clamp sensor
is completely closed. This does not signal a malfunc-
tion. Check the current flowing through the grounding
wire by using the instrument's current measurement
mode or an instrument such as a clamp tester capa-
ble of DC current measurement.
HIOKI FT6380B981-01
www.calcert.com
1.800.544.2843
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