Notes Related To Measurement Functions - Elma Instruments iTest 7400 Manual

2.1.3.2 Insulation resistance
•
Insulation resistance measurement should only be performed on de-energized objects!
•
Ensure all loads are disconnected and all switches are closed when measuring insulation resistance
between installation conductors.
•
Avoid contact with the test object during measurement or before it is fully discharged to prevent the risk
of electric shock.
2.1.3.3 Continuity functions
•
Continuity measurements should only be performed on de-energized objects!
•
Parallel impedances or transient currents may influence test results.
2.1.3.4 Testing PE terminal
•
If phase voltage is detected on the tested PE terminal, stop all measurements immediately and ensure
the cause of the fault is eliminated before proceeding with any activity!

2.1.4 Notes related to measurement functions

2.1.4.1 General
•
The "!" indicator means that the selected measurement cannot be performed because of irregular
conditions on input terminals.
•
Insulation resistance, continuity functions and earth resistance measurements can only be performed
on de-energized objects.
•
PASS / FAIL indication is enabled when limit is set. Apply appropriate limit value for evaluation of
measurement results.
•
In the case that only two of the three wires are connected to the electrical installation under test, only
voltage indication between these two wires is valid.
2.1.4.2 Insulation resistance
•
If voltages of higher than 10 V (AC or DC) are detected between test terminals, the insulation
resistance measurement will not be performed.
2.1.4.3 Continuity functions
•
If voltages of higher than 10 V (AC or DC) are detected between test terminals, the continuity
resistance test will not be performed.
•
Before performing a continuity measurement, where necessary, compensate test lead resistance.
2.1.4.4 RCD functions
•
Parameters set in one function are also kept for other RCD functions!
•
The measurement of contact voltage does not normally trip an RCD. However, the trip limit of the RCD
may be exceeded because of leakage current flowing to the PE protective conductor or a capacitive
connection between L and PE conductors.
•
The RCD trip-lock sub-function (function selector switch in LOOP position) takes longer to complete but
offers much better accuracy of fault loop resistance (in comparison to the Rl sub-result in contact
voltage function).
•
RCD trip-out time and RCD trip-out current measurements will only be performed if the contact voltage
in the pre-test at nominal differential current is lower than the set contact voltage limit!
•
The auto-test sequence (RCD AUTO function) stops when trip-out time is out of allowable time period.
2.1.4.5 Loop impedance (with Loop RCD and/or Loop Rs option)
•
Isc depends on Z, Un and scaling factor
•
The current limit depends on fuse type, fuse current rating, fuse trip-out time
•
The specified accuracy of tested parameters is valid only if the mains voltage is stable during the
measurement.
•
Fault loop impedance measurements will trip an RCD.
•
The measurement of fault loop impedance using trip-lock function does not normally trip an RCD.
However, the trip limit may be exceeded as a result of leakage current flowing to the PE protective
conductor or a capacitive connection between L and PE conductors.
Elma iTest 7400 Multifunction tester
6