PCE Instruments Chauvin Arnoux C.A 6421 Bedienungsanleitung Seite 19

Checking measurement readings
7. Write down the measurement reading.
8. Repeat the measurement after a while.
9. Move the rod S toward H over a distance equal to 10% of "a". Start the measurement and
write down the reading.
10. Move the rod S from its initial location toward E, over a distance equal to 10% of "a". Start
the measurement and write down the reading.
The measurement is correct if all three readings have the same order of magnitude.
Otherwise, increase "a" and repeat the above steps.
Do not forget to connect the earth connection again after the test.
3.1.1. Measurement using the " triangular " method
Switch off the installation and disconnect it from the ground by opening the
earthing rod!
1. Connect terminal E to the earth connection to be tested.
2. Check that the bar 4 was not installed between terminals S and H.
3. Push down the rods S and H into the earth as deeply as possible, in order that they form
with the earth connection an equilateral triangle E - S - H.
Earth resistance measurement using the triangular method
4. Press the pusbutton 11 till the galvanometer
pointer stabilizes. Make sure none of the three
indicators is blinking, otherwise check the
connections (see § 3.3: FAULT INDICATIONS)
and repeat the measurement. Write down the
reading.
5. Move the rod S (without moving H) in order
to form a new triangle E - S' - H.
6. Start a new measurement and compare the
reading with the previous one. The
measurement will be considered as correct if
there is little difference between the two
readings (only some %).
indicates that the rod S is located within a
vicinity area. Make the triangle much larger
and repeat the above steps.
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Otherwise, this