Loop Impedance (Line To Protective Earth L-Pe) - Beha-Amprobe Telaris Série Guide D'utilisation

Loop Impedance (Line to Protective Earth L-PE)

Loop impedance is source impedance measured between Line (L) and Protective Earth (PE).
You can also ascertain the Prospective Earth Fault Current (PSC) that is the current that could
potentially flow if the phase conductor is shorted to the protective earth conductor. The
tester calculates the PSC by dividing the measured mains voltage by the loop impedance.
The loop impedance function applies a test current that flows to earth. If RCDs are present
in the circuit, they may trip. To avoid tripping, always use the Zl No Trip function on the
rotary switch. The no trip test applies a special test that prevents RCDs in the system from
tripping. If you are certain no RCDs are in the circuit, you can use the Zl Hi Current function
for a faster test.
Note: If the L and N terminals are reversed, the tester will auto-swap them internally and
continue testing. If the tester is configured for UK operation, testing will halt. This condition
is indicated by symbol (
To measure loop impedance no trip mode:
WWarning
To prevent tripping RCDs in the circuit:
• Always use the
• Preload conditions can cause the RCD to trip.
• An RCD with a nominal fault current of 10 mA will trip.
Note: To do a Loop impedance test in a circuit with a 10 mA RCD, we recommend a trip time
RCD test. Use a nominal test current of 10 mA and the factor x ½ for this test.
If the fault voltage is below 25 V or 50 V, dependent on the local requirement, the loop is
good. To calculate the loop impedance, divide the fault voltage by 10 mA (Loop impedance
= fault voltage x 100).
1. Turn the rotary switch to the
2. Connect all three leads to the L, PE, and N (red, green, and blue) terminals of the tester.
Only the calibrated test lead which are in scope of supply must be used! The resistance
of the calibrated test leads is subtracted from the result automatically.
3. Press F1 to select L-PE. The display shows the Z
4. Connect all three leads to the L, PE, and N of the system under test or plug the mains
cord into the socket under test.
4. Press and release
the loop impedance. The secondary (lower) display shows the prospective short current
(PSC) in amps or kilo amps.
This test will take several seconds to complete. If the mains is disconnected while the test is
active, the test automatically terminates.
Note: Errors may occur due to preloading the circuit under test.
).
position for loop measurements.
position.
Figure 12. Display After Zeroing
. Wait for the test to complete. The primary (upper) display shows
and indicator.
L
12