METREL MI 3399, Инструкция с упражнениями

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Electrical Installation Safety Trainer AD 1 - MI 3399
108
As seen from the results above the measurement in a TN system (left) is below the
threshold and the test passed. The test in a TT system (right) is marked as failed. Since
this test actually measured earth resistance the test result should be considered as
passed regardless of what the device is telling us. The device does not distinguish
between TN and TT earthing systems so it cannot predict the type of earthing system
used. It is up to the user set the limit for the R
PE
test in order for the device to correctly
interpret the results.
Expected results with a simulated error
A typical fault when measuring continuity would be if the resistance of PE conductor
would be above 2
Ω. To simulate such an error enable the switch
S19 in the Application
Trainer.
Figure 2-46: Simulated continuity error
E
xer
ci
ses
S
w
itch
Function Site of error ON OFF
S15 R LOW / IMD
IT F3/1
PE outlet
> 20
Ω
< 1
Ω
S16 ISFL / IMD
IT F3/2
ISFL approx. 6 mA (@ 230 V)
approx. 3 mA (@ 115 V)
< 1.3 mA
S17 R LOW IT PE ref.
approx. 3.3 Ω < 1 Ω
S18 R LOW
TN/TT F1/4
PE light
> 20
Ω < 1 Ω
S19 R LOW / Z LOOP
TN/TT F1/2
PE outlet (3-ph.)
approx. 3.4 Ω < 1 Ω
S20 R LOW / Z LOOP
TN/TT F2/2
PE outlet
> 2.3
Ω < 2 Ω
S21 R LOW MPE / PE Gas
approx. 2.2 Ω < 1 Ω
S22 R LOW MPE / PE Heat inst.
approx. 3.3 Ω < 1 Ω
P
E
C
o
n
n
e
c
tio
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