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8.2.2 Measurement without Guard Terminal
For most tests, only two test leads are used. Connect the red test probe and black alligator with the measured
object as shown in Picture 6.
8.2.3 Measurement Using Guard Terminal
When measuring the insulation resistance from the conductor to the outer sheath of a cable, there may be a
leakage current for the intermediate layer, causing measurement error. To prevent such error, connect the green
test lead directly to the leakage current winding end (as shown in Picture 7), and the leakage current portion will
not be counted in the displayed value. The reading value is only the insulation 3resistance from the conductor
to the outer sheath of the cable.
Picture 6
Picture 7
Note: Measurement using guard terminal is suitable for testing the entire circuit of a high voltage cable
containing other high voltage equipment. Connect the GUARD terminal to the leakage current electrode of the
measured object, and EARTH terminal to the green test lead. At this time, the leakage current cannot flow into
the EARTH terminal for calculation. However, for this measurement method, the insulation resistance of the
sheath (between the shielded cable and the ground) must be >1MΩ.
UT516B User Manual
UT516B User Manual
