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Checklist for Insulation Tests
2
Test Voltage
2.1
Check whether the test electrode has high voltage as follows:
Switch on the tester and hold the test button depressed. When the electrode
is now earthed, a continuous spark-over must occur. The buzzer sounds
continuously.
2.2
Is the test voltage correctly set?
DIN 30 672, section 5.5.5, prescribes:
The test voltage is 5 kV + 5 kV per mm of coat thickness.
Caution: Beware of overlapping areas of resheathings or works sheathings.
In the case of polyurethane-tar or epoxy resin coatings, observe DIN 30 667
and the manufacturer's instructions.
2.3
Is the test voltage monitored with a sphere gap?
DIN 30 672, section 5.5.5, prescribes a sphere gap as obligatory. Point gaps
are particularly susceptible to changes in atmospheric pressure and humidity
and can, under certain circumstances, result in seriously incorrect settings of
the test voltage.
ELMED testers have an automatic control system with integral sphere gap.
The function of the sphere gap can be heard as a light tapping sound in the
tester or test rod. Monitoring of the test voltage using a separate measuring
spark gap is not necessary thanks to the continuous self-calibration of the test
voltage.
