Electrical Installation Tester
Making Measurements
35
The earth resistance test is a 3-wire test consisting of two test stakes and the
earth electrode under test. This test requires an accessory stake kit. Connect
as shown in Figure 20.
• Best accuracy is achieved with the middle stake at 62 % of the distance to
the far stake. The stakes should be in a straight line and wires separated to
avoid mutual coupling.
• The earth electrode under test should be disconnected from the electrical
system when conducting the test. Earth resistance testing should not be
performed on a live system.
62% L
L
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Figure 20. Earth Resistance Test Connection
To measure earth resistance:
1. Turn the rotary switch to the position.
2. Press and release . Wait for the test to complete.
• The primary (upper) display shows the earth resistance reading.
• Voltage detected between the test rods will be displayed in the
secondary display. If greater than 10 V, the test is inhibited.
• If the measurement is too noisy, Err 5 will be displayed. (The
measured value accuracy is degraded by the noise). Press the down
arrow () to display the measured value. Press the up arrow () to
return to the Err 5 display.
• If the probe resistance is too high, Err 6 is displayed. Probe resistance
may be reduced by driving the test stakes further into the earth or
wetting the earth around the test stakes.
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