METREL MI 3122 User Manual

MI 3122 Smartec Z Line-Loop / RCD Fault loop impedance
31
Fault loop impedance measurement procedure
 Select the Z-LOOP function using the function selector switch.
 Select test parameters (optional).
 Connect test cable to the top of the Smartec Z Line-Loop / RCD.
 Connect test leads to the item to be tested (see figure 5.9).
 Press the TEST key to perform the measurement.
 Store the result by pressing the MEM key (optional).
UK version
Figure 5.10: Examples of loop impedance measurement result
Displayed results:
Z .............. Fault loop impedance,
ISC ............ Prospective fault current,
Lim .......... Low limit prospective short-circuit current value or high limit fault loop
impedance value for the UK version.
Prospective fault current I
SC
is calculated from measured impedance as follows:
Z
kUn
I
SC
SC


where:
Un ........ Nominal U
L-PE
voltage (see table below),
ksc ....... Correction factor for Isc (see chapter 4.2.6).
U
n
Input voltage range (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.

This measurement will trip-out the RCD in RCD-protected electrical installation if
test Zloop is selected.
 Select Zs rcd to prevent trip-out of RCD in RCD protected installation.

METREL MI 3122 Specifications

General

Brand	METREL
Model	MI 3122
Category	Multimeter
Language	English