Multifunction Tester
Measurements
47
RCD Tests in IT Systems
RCD tests at locations with Insulated-Terra Power Distribution Network (IT Systems) require a
special test procedure because the Protective Earth connection is grounded locally and is not
tied directly to the power system.
The test is done at the electrical panel with probes. See Figure 17 for the connections used in
this test.
Figure 17. Connection for RCD Test on IT Electrical Systems
To test RCD type B or RCD type A-EV in an IT system, use the connections shown in Figure 18.
Figure 18. Connection for Test of RCD Type B or RCD Type A-EV on IT Electrical Systems
The test current flows through the upper side of the RCD, into the L terminal, and returns
through the PE terminal.
To test an RCD at the mains socket, put the Tester into the IT mode. In this mode the Tester
accepts any voltage between N and PE. The precondition for trip time and current
measurements is that the system capacitance is high enough to allow the test current to flow.
To Next Page
