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6
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Three-wire Test Grounding Resistance
Three-wire test: As shown below, short-circuit the ES, E interface of
the instrument, which is a three-wire test, instrument operation is the same
as four-wire test.The three-wire test cannot eliminate the influence of the
wire resistance on the measurement, nor can it eliminate the influence of
the change of the contact resistance between the instrument and the test wire
and the influence of the change between the test wire and the auxiliary
grounding rod. When measuring, the oxide layer on the surface of the ground
body to be measured must also be removed.
7
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Two-wire Easy Test Grounding Resistance
Two-wire test:: This method is a simple measurement method that does not
use the auxiliary grounding rod. It uses the grounding electrode with the
smallest value of the grounding resistance as the auxiliary grounding
electrode, and uses two simple test lines to connect the HS interface and
the E-ES interface. ).The auxiliary ground rods H and S may be replaced with
metallic ground pipes such as metal water pipes and fire hydrants, common
grounding of commercial power systems, or lightning protection grounds of
buildings, etc., take care to remove the oxide layer at the connection point
of the selected metal auxiliary grounding body during measurement. Wiring
as shown below, the instrument operation same as the four-wire test.
When using the commercial power system grounding as an
auxiliary grounding pole measurement, it must be confirmed
that it is the grounding pole of a commercial power system.
Otherwise, the circuit breaker may start up and be in danger.
Use a simple two-wire method to measure the grounding
resistance, and try to select the grounding body with a small
re value as the auxiliary grounding electrode so that the
meter reading is closer to the true value. When measuring,
Please take precedence to choose the metal water pipe and
metal fire hydrant as the auxiliary grounding electrode.
Summary of Contents for ES3001
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