KYORITSU 4105A - Manual (Page 8)

w Earth Voltage Measurement
Set the range switch to EARTH VOLTAGE position in the condition of
q . Earth voltage will be indicated on the display. Make sure that the
voltage is 10V or less.
When the display reads more than 10V, it may result in excessive
errors in earth resistance measurement. To avoid this, make
measurement after reducing the voltage by turning off the power
supply of the equipment under test etc.
e Simplified Measurement
Set the range switch to 2000 Ω position and press the test button. LED
remains illuminated during testing. Turn the range switch to 200 Ω and
20 Ω when the earth resistance is low. This indicated value is the earth
resistance of the earthed equipment under test.
Note : If the auxiliary earth resistance of auxiliary earth spike C is too
high to make measurement, the display reads ' . . . '. Recheck the
connection of each test lead and the earth resistance of auxiliary
earth spike.
r Simplified Measurement Value
Two-terminal method is used for simplified measurement. In this
method, earth resistance value re of earth electrode connected to
terminal P is added to true earth resistance value Rx and shown as
an indicated value Re.
Re = Rx + re
If the re is known beforehand, true earth resistance value Rx is
calculated as follows.
Rx = Re --- re
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Note : When the simplified measurement probes are not used, short P
and C terminals.
DANGER
Please be sure to use a voltage detector to check a common earth of
commercial power supply.
Do not use the instrument to check a common earth of commercial
power supply.
A danger will be caused because the voltage may not be displayed
even in case of a live conductor when the connection of the earth
electrode to be measured has come off, or when the connection of the
test leads of the instrument is not correct etc.
Do not use the instrument to measure the voltage of commercial power
supply.
The instrument is not designed for voltage measurement of commercial
power supply. When using the adjunctive simplified measurement
probe MODEL 7127, P and C terminals will be short-circuited and the
input impedance will be reduced. The residual current circuit breaker
may operate when making measurement of the voltage in the circuit
with the breaker.
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