Martindale ET4000 / ET4500 Measurements
45
5.5 Fault loop impedance and prospective fault current
Fault loop is a loop comprised of the mains source, line wiring and the PE path back to
the mains source. The instrument measures the impedance of the loop and calculates
the short circuit current. The measurements conform to BS EN 61557-3.
See chapter 4.3 Function selection for
instructions on key functionality.
Figure 5.25: 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 [---, BS88-2, BS3036, BS88-3, BS1362, B, C, D]
Fuse I
Rated current of selected fuse
Fuse T
Maximum breaking time of selected fuse
Lim
Upper limit fault loop impedance value for selected fuse
See Appendix A for reference fuse data.
Circuits for measurement of fault loop impedance
Figure 5.26: Connection for measurement of fault loop impedance
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