METREL Eutrotest PB, Инструкция по эксплуатации

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MI 3108 EurotestPV Measurements
– a.c. LV installations
60
Fault loop impedance measurement procedure

Select the Zloop or Zs rcd sub-function using the function selector keys and

/

keys.

Select test parameters (optional).

Connect test cable to the instrument .

Connect test leads to the item to be tested (see figures 5.29 and 5.21 ).

Press the TEST key to perform the measurement.

Store the result by pressing the MEM key (optional).
Figure 5.30: Examples of loop impedance measurement result
Displayed results:
Z .............. Fault loop impedance,
I
SC
............ Prospective fault current,
Lim .......... High limit fault loop impedance value.
Prospective fault current I
PFC
is calculated from measured impedance as follows:
factor scaling Z
U
I
PE L
N
PFC
_



where:
Un ........ Nominal U
L-PE
voltage (see table below),
Scaling factor.......Impedance correction factor (see chapter 4.4.5 ).
U
n
Input voltage (L-PE)
110 V (93 V

U
L-PE

134 V)
230 V (185 V

U
L-PE

266 V)
Notes:

High fluctuations of mains voltage can influence the measurement results (the
noise sign
is displayed in the message field). In this case it is recommended to
repeat few measurements to check if the readings are stable.

The Zloop test will trip-out the RCD in RCD-protected electrical installation.

Select Zs
rcd
to prevent trip-out of RCD in RCD protected installation.