METREL MI 3399, Инструкция с упражнениями

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Electrical Installation Safety Trainer AD 1 - MI 3399
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Figure 2-46: Simulated continuity error ................................................................... 108
Figure 2-47: Chart reference for earth resistance measurements .......................... 110
Figure 2-48: Earth resistance measurement using the 3-wire method ................... 110
Figure 2-49: Earth resistance measurement in a TT system using the 2 clamp method
............................................................................................................................... 110
Figure 2-50: Lightning system testing ..................................................................... 111
Figure 2-51: Two-wire test (only for TT systems), no probes .................................. 112
Figure 2-52: Total earthing measurement (3 wires)
– standard method ................. 113
Figure 2-53: Selective earthing measurement
– standard method ......................... 113
Figure 2-54: Three-wire test, two probes, and equilateral placement of probes ..... 114
Figure 2-55: Equilateral placement of probes ......................................................... 114
Figure 2-56: Total earthing resistance measurement with two current clamps ....... 115
Figure 2-57: Test system (individual earthing rods) with two current clamps ......... 116
Figure 2-58: Measurement of resistance to earth of object with two current clamps in
TN system .............................................................................................................. 116
Figure 2-59: Simulated earth resistance errors ....................................................... 118
Figure 2-60: Simulated earth resistance error in a TN earthing system .................. 121
TABLE OF TABLES:
Table 1-1: Maximum allowed fault loop impedances in case of used melting fuses type
B, C and gG .............................................................................................................. 41
Table 1-2: Fuse trip-out times ................................................................................... 41
Table 1-3: Trip-out times according to IEC 60364-4-41 ............................................ 42
Table 1-4: Trip-out currents according to IEC/TR 60755 .......................................... 42
Table 1-5: Maximum allowed earth resistance (Z
L-PE
) values for RCD protected
installations ............................................................................................................... 43
Table 2-1: Nominal voltage table .............................................................................. 51
Table 2-2: Insulation resistance limits ....................................................................... 91