Gx
Series
EN - 37
6.4. LOOP: LINE
IMPEDANCE/LOOP AND OVERALL EARTH RESISTANCE
This function is performed in compliance with standard IEC/EN61557-3, BS7671 17th
edition, AS/NZS 3000, AS/NZS 3017 and allows measuring the line impedance, the fault
loop impedance and the prospective short-circuit current.
CAUTION
Depending on the selected electrical system (TT, TN or IT) some kind of
connection and function modes are disabled by the instruments (see Table 2 )
The following operating modes are available
L-N
Standard (STD) measurement of the line impedance between the phase
conductor and the neutral conductor and calculation of the assumed phase-
to-neutral short-circuit current. This measurement is carried out even with
high resolution (0.1m
) through the optional accessory IMP57.
L-L
Standard (STD) measurement of the line impedance between the two phase
conductors and calculation of the assumed phase-to-phase short-circuit
current. This measurement is carried out even with high resolution (0.1m
)
through the optional accessory IMP57.
L-PE
Standard (STD) measurement of the fault loop impedance between the
phase conductor and the earth conductor and calculation of the assumed
phase-to-earth short-circuit current. This measurement is carried out even
with high resolution (0.1m
) through the optional accessory IMP57.
No
Trip
Loop impedance without causing the protections tripping in TN systems (see
§ 13.6) and Global earth resistance (TT systems) with and without neutral
(see § 13.7).
CAUTION
The measurement of line impedance or fault loop impedance involves the
circulation of a maximum current according to the technical specifications of
the instrument (see § 11.1). This could cause the tripping of possible
magnetothermal or differential protections at lower tripping currents.
Fig. 18: P-N/P-PE measure for single-phase 230V systems with shuko plug
Fig. 19: P-N/P-PE measure for single-phase/two-phase 230V systems with cables and
remote lead