Fluke 1650B [26/62] Measuring loop line impedance

Fluke 1650B [26/62] Measuring loop line impedance
165XB
Users Manual
18
subtracts it from readings. The resistance value is saved even when power
is turned off so you don’t need to repeat the operation every time you use
the instrument.
4. Press and hold T until the reading settles. If the continuity beeper is
enabled, the tester beeps continuously for measured values less than 2 Ω
and there is no stable reading beep for measured values greater than 2 Ω.
If a circuit is live, the test is inhibited and the AC voltage appears in the
secondary (lower) display.
Measuring Loop/Line Impedance
apx006f.eps
Figure 10. Loop/Line Impedance/Switch and Terminal Settings
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 (PEFC) that is the current that could potentially flow if the phase
conductor is shorted to the protective earth conductor. The tester calculates the
PEFC 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 Z
l
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 Z
l
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 arrows above
or below the terminal indicator symbol (b).

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