Continuity Testing; Fig.20 Continuity Testing - Megger DET5/4R Guia Del Usuario

MEASURING TECHNIQUES Continuity Testing
The DET 5/4 will measure metallic resistances of low
inductance or capacitance. To test the continuity of
conduit or other earth conductors the instrument can
be connected as a 4 pole tester, or connected as
shown in Fig. 20. Ensure that the circuit is de-
energised, before connecting the instrument for
measurement.
Note:- Due to the inherent high accuracy of the
instrument and the low continuity resistance to be
measured, contact resistance between the test lead
clips and the conduit becomes a factor in the measured
value. Contact resistance should therefore be kept as
low as possible.
1) Using a shorting bar supplied, short together
terminals 'P2' and 'C2'.
2) Firmly connect a test lead to 'C1',and the other
test lead to 'P2' and 'C2'.
3) Firmly connect the free ends of the test leads
across the isolated circuit under test.
4) Press the 3 pole test push, and take a reading in
the normal way.
The resistance of the two test leads can be found by
firmly joining their free ends together, pressing the
3 pole test push and taking the reading in the usual
way. Test lead resistance can then be subtracted from
the original reading, to give a 'true' value of continuity
resistance.
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P1 P2
C1 C2
E ES S H
® EARTH EARTH
R MEGGER MEGGER DET5/4D DET5/4D TESTER TESTER
k
3 POLE 4 POLE
MEASURE R
E
Fig. 20 Continuity testing.