performing an insulation resistance test, and ensure all necessary
health and safety precautions are observed.
Automatic Discharge: Capacitive circuits are automatically
discharged when the test button is released following an insulation
test.
The circuit under test must be completely de-energised and
securely isolated before test connections are made.
Standard insulation resistance testing
1. Connect the test probes to the isolated circuit under test.
2. Turn the instrument ‘ON‘ by rotating the selector switch to the
desired test voltage.
3. Press and hold the [TEST] button to start the test.
4. The insulation resistance value, in both analogue and digital form
is displayed together with the actual test voltage displayed on the
secondary display.
5. The insulation test can be locked on, by pressing the lock button
[
] whilst holding down the [TEST] button. To disable lock
press the [TEST] button or lock [
] button.
6. By pressing the [uA/V/s] button, the leakage current can be
displayed.
7. Release the [TEST] button before removing the test leads (to
enable the instrument to discharge the circuit under test). If the
display shows VOLTS, wait until it reaches zero.
8. On completion of testing, switch to the ‘
OFF
’ position.
Insulation resistance testing – timed modes ‘t’, PI and
DAR
Three types of timed test are possible:
(a) Standard count down timer (t)
Timed tests are performed over a timed period defined by
parameter ‘t’ (also refer to Set-up procedures 13).
(b) Polarization Index (PI)
PI is the ratio between the insulation resistance values recorded at
1 minute (assigned t1) and at 10 minutes interval (assigned t2). i.e.
after 1 minute and 10 minutes.
PI = 10 minute value/1 minute value
(c) Dielectric Absorption Ratio (DAR)
Audible alarm
indicator
