MARTINDALE ET4000 Instruction Manual page 49

Martindale ET4000 / ET4500
5.6.1 Line impedance and prospective short circuit current
Circuits for measurement of line impedance
Figure 5.30: Phase-neutral or phase-phase line impedance measurement
Line impedance measurement procedure
Select the Z LINE

Set sub-function to

Select test parameters (optional).

Connect the test leads to the instrument.

Connect the test leads to the installation wiring to be tested (see Figure 5.30).

Press the TEST key to perform the measurement.

Store the result, if required, by pressing the MEM key (ET4500 only).

Figure 5.31: Examples of line impedance measurement result
Displayed results:
Z .............. line impedance
Isc ........... prospective short-circuit current
Lim .......... upper limit line impedance value
Prospective fault current I
where:
Un ........................ Nominal U
Scaling factor ....... Impedance correction factor (see chapter 4.4.4 Z factor).
function using the function selector switch.
Zline using UP / DOWN keys.
is calculated from the measured impedance as follows:
PFC

I

PFC
Z scaling

L N ( L )
or U voltage (see table below),
L-N L1-L2
49
U
N
_ factor
Measurements