MZC-304
– USER MANUAL
8
2.7.2 Prospective short-circuit current
The meter always measures impedance. The short-circuit current is calculated according to the
following formula:
S
n
k
Z
U
I
where: U
n
- mains rated voltage, Z
S
- measured impedance.
On the basis of U
n
rated voltage selected (section 2.1), the meter automatically recognizes the
measurement at phase-to-neutral or phase-to-phase voltage and takes it into account in the calcula-
tions.
If the voltage of the tested mains is outside the tolerance range, the meter will not be able to de-
termine a proper rated voltage for the short-circuit current calculation. In such a case, horizontal
dashes will be displayed instead a short-circuit current value. The following diagram shows voltage
ranges for which short-circuit current value is calculated.
230
400
440
U [V]
Voltage ranges
for which the
short-circuit current is calculated
U ,
L-N
Voltage range for which the impedance is measured
207
253
360
220
380
418
198
242
342
373
415 440
216 240
264
440
U [V]
U [V]
U =220V
n
U =230V
n
U =240V
n
Voltage ranges U , for which the
short-circuit current is calculated
L.-L
2.7.3 Measurement of fault loop parameters in the L-N and L-L circuits
Turn on the meter.
Turn the rotary switch
to the
Z
L-L
Z
L-N
position.
Depending on needs, select cable length according to section 2.7.1.
