One-Point Grounding System - VOLTCRAFT EMZ-1000 Bedienungsanleitung

c) One-point grounding system
Based on its measuring principle, the tester can only measure the loop resistance, but not the
single-point grounding. The user can also artificially create a test loop using a test lead and the
grounding electrode near the grounding system. Below you will find a description of two methods
of measuring single-point grounding with the tester. These methods can be used on occasions
which are not part of the traditional method of testing voltage and current.
A) Two point method
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Find an independent grounding body with a better grounding status RB (e.g. a nearby water
pipeline or building) near the measured grounding body RA, as shown in the figure below. Con-
nect RA and RB to the test lead.
EMZ-1000
The resistance value measured by the tester is the array value of the two grounding resistances
and the test lead resistance.
RT = RA + RB + RL
Where: RT is the resistance value measured by the tester.
RL is the resistance value of the test lead.
RL can be measured with the tester by end-to-end connection of the test lead.
The grounding resistance of the two grounding bodies is considered qualified if the tester read-
ing is less than the permissible grounding resistance value.
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