eSpace IAD
Troubleshooting
3 Co mmon Troubleshooting Methods
Issue 02 (2012-02-29)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
96
impedance does not meet the requirements, report the fact and monitor the rectification, such
as, rebury the ground electrode or verify the ground conductor connections.
shows the ground impedance tester.
Figure 3-25
Ground impedance tester
Ground Impedance Test Method
Impedance Requirements
AC working ground: not greater than 4 ohms.
Security working ground: not greater than 4 ohms.
DC working ground: determined by the actual devices.
Lightning protection ground: not greater than 10 ohms.
Joint shielded system ground: not greater than 1 ohms.
Resistance Tester Introduction
ZC-8 resistance tester is used to test the ground resistance of power supply systems,
telecommunication devices, and lightning rods. IT can also test the resistance of
low-resistance conductors and soil resistivity. The tester consists of a handle electric generator,
current mutual-inductors, sliding resistor, and galvanometer. All these components are packed
in plastic. In addition, probes and conductors are provided with the tester.
Preparation for Resistance Test
Prepare the following tools:
ZC-8 resistance tester.
Two test probes.
Three conductors with the length of 5 m, 20 m, and 40 m.
Before impedance test, connect a 5 m conductor to point E, a 20 m conductor to point P, and a
40 m conductor to point C, and connect the other ends of the conductors to ground electrode
E', potential probe P', and current probe C' respectively. Points E', P', and C' must be on a
straight line and the distance between each other is 20 m.
shows the connection diagram for testing impedance greater than or equal to 1
ohm.