MI 3100 s, MI 3100 SE
Eurotest
EASI
Measurements
44
5.5
Fault loop impedance and prospective fault current
Fault loop is a loop comprised by mains source, line wiring and PE path to the mains source.
The instrument measures the impedance of the loop and calculates the short circuit current.
The measurement is covered by requirements of the EN 61557-3 standard.
on key functionality.
Figure 5.23: Fault loop impedance
Test parameters for fault loop impedance measurement
Test
Selection of
fault loop impedance sub-function
[Zloop, Zs rcd]
Fuse type
Selection of
fuse type
[---, NV, gG, B, C, K, D]
Fuse I
Rated current
of selected fuse
Fuse T
Maximum breaking time
of selected fuse
Lim
Minimum short circuit current
for selected fuse
See Appendix A for reference fuse data.
Circuits for measurement of fault loop impedance
Figure 5.24: Connection of plug commander and 3-wire test lead
