65
Note that the instrument allows measurement of loop impedance LPE behind 30mA circuit-breakers
without causing them to trip (principle patented by Chauvin Arnoux).
In an IT network, use the instrument's "ZLINE" function.
The measurement principle is the same as for an earth measurement in a live condition.
When the TEST key is pressed, the instrument:
- checks that the amplitude and frequency of the voltages present are correct,
- measures the voltage between the TEST key and terminal PE,
- interchanges L and N internally if the 2 conductors are reversed in the socket,
- generates a current (high or low according to the user's selection) between terminals L and
PE,
- measures loop impedances Z
LN
, Z
LPE
, and Z
NPE
.
Note:
the measurement of Z
LN
does not trip the earth fault breakers even with high currents.
4.3.2 PREPARATION FOR THE MEASUREMENT (CONNECTION))
→
If necessary, in "SET-UP" mode:
-
set threshold voltage U
L
(see § 3.2),
-
the type of compensation of the measuring cables (see § 3.3))
-
set the alarm threshold Z
L
or R
L
(see § 4.2.2)
-
possibly, select a value of U
REF
to be used for the calculation of the short-circuit current:
-
the current generated for the measurement in low current mode (see § 4.2.2),
-
set the number of measurements to be counted to smooth the measurement (see § 3.2)
→
Set the switch to the ZLOOP position;
→
Activate the alarm by pressing the ALARM key,
→
Connect the line power plug or the 3 separate cables to the installation to be tested,
→
Compensate the measuring cables (see § 3.3),
→
Select the measuring current:
→
high (
) for a greater accuracy:
PUSH
btn
U
REF
MEAS
I
k
PUSH
btn
selection of voltage:
MEAS/230/400/127 or MEAS/220/380/110
MORE
x 4
MORE
x 3
Summary of Contents for C.A 6454
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