7
Checking earth faults
Earth faults on the monitoring cores must be checked
for and avoided as they may cause spurious seal
leakage indications. Fault finding of this nature should
only be carried out using a multimeter ohms scale and
not an insulation tester utilising 500 V or above as a
test voltage.
Measure between each sensor lead and earth. Ideally
the value should be infinite but Mega ohm values are
acceptable.
To be noted
A zero current may be the result of a broken sensor
lead or an open thermal switch.
A leakage alarm may be caused by a short circuit due
to pinched sensor leads or a correct leakage signal
from FLS, FLS10 or CLS.
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