Alternative Procedure; Measuring Earth Resistance - Beha-Amprobe Telaris Série Guide D'utilisation

Figure 18. Connection for RCD Testing on IT Electrical Systems
The test current flows through the upper side of the RCD, into the L terminal, and returns
though the PE terminal.

Alternative procedure

In IT systems, when testing an RCD at a mains socket: Use the mains test lead but do not
connect the N-wire to the instrument, so just the PE and L inputs are used. See figure 18a.

Measuring Earth Resistance

Figure 19. Earth Resistance Display/Switch and Terminal Settings
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.
Mains Supply
PE (L2/Green)
B
G
RCD
N (L3/Blue)
L (L1/Red)
R
Figure 18a.
18