Fluke 165X - Measuring Loop and Line Impedance

165X
Users Manual
24
Measuring Loop/Line Impedance
.
Z
I
apx006f.eps
Figure 10. Loop/Line Impedance/Switch and Terminal
Settings
Loop Impedance
Loop impedance is source impedance measured between
Line and Protective Earth. You can also measure the
Prospective Fault Current (PFC) which is the current that
could potentially flow if the phase conductor is shorted to
the protective earth conductor. The tester calculates the
PFC by dividing the measured mains voltage by the loop
impedance.
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 and you will need to
manually swap the terminals. This condition is
indicated by arrows above or below the terminal
indicator symbol (
b ).
To measure loop impedance
1. Turn the rotary switch to the Z
I
position.
2. Press 1 to select L-PE.
3. Before measuring, zero the test probes by shorting all
three leads together at the far end (away from the
tester) and press the Z button. To zero the mains
cord, wrap a piece of bare wire around the terminals
of the plug and press the Z button. The tester
saves the zero offset so you don’t need to repeat the
operation every time you use the tester.
XW Warning
Remove the bare wire before proceeding with
the test.