ZL
BROWN
RN
BLUE (N)
RK
RE
GREEN (PE)
RK
v
In the first stage the Live-Neutral loop impedance ZLN is measured using the same
principle as for Live-Earth loop.
The second stage is similar to Hi-I but operates at a low current to avoid tripping
RCDs
Caution
Although fully protected against over voltage to 550VAC this tester should only be
used on a 230V supply.
Important note for calibration check box users: The smart loop test system used by
the Socket & See MFT5000 is immune to sudden high value changes such as voltage
spikes. As a result when changing calibration or check box loop values the tester or
the supply must be switched o between changes of calibration values.
Loop Impedance Testing
Principle of Measurement – No-Trip
The No-Trip Line-Earth loop range measures the same circuit value ZI using a two-stage
technique.
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