Isolation - EXFO MaxTester 635G User Manual

Multimeter Tests

Isolation

Isolation
The Isolation test, also known as a leakage test, is a type of resistance test
run over a period of time to look for high-resistive faults. This test applies
more measuring voltage than standard resistance tests (typically 100 VDC)
over a longer period of time or Soak Time. The purpose is to allow the
applied higher voltage to leak through corrosion or high resistive faults,
revealing the fault by the drop in the measured resistance value. Standard
resistance tests use lower voltages (15 to 45 V) only for a short period of
time.
Snapshot
The Isolation (also known as insulation resistance) test shows how the
pair insulation (that is PIC or paper, pulp, etc.) may be lower because of
long-term voltage on the pair under test. (Remember that telecom signals
are full time.) This is especially important for power span pairs carrying
significant voltages over time. Be aware that the continuous application of
a voltage tends to dry up moisture, and some faults may seem to
disappear. (You would see the resistance value increase and thus improve
as the test progresses; however, the cause of the moisture is not resolved.)
Note: The test should be run with an open circuit at the far end.
The Snapshot page shows measured isolation
resistance values for each lead combination. The
parameters are as follows:
Current Group is the current test group name, for

example Multimeter.
Current Test displays the test being measured.

Here you can switch to another test from the given
list. However, this action will terminate the
ongoing measurement test.
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