Megger Digiflex Com, Instruction Manual

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3.8.1.1 Faults Causing a Negative Reflection
(1) Short circuit: Direct contact of two conductors of a cable. This will
cause a negative reflection, see Fig 4.
Fig 4 Type of Fault Causing a Negative Reflection
(2) Short-circuit to shield: One conductor in a cable is in contact with the
metal shield of the cable. For locating this type of short-circuit, first
disconnect earth from the shield. Then connect the test leads to the
shield and the conductor which is shorted with it.
(3) Reversed (mixed-up) wires: Reversed wires generate a reflectogram
similar to a short circuit but reflections are smaller in size.
3.8.1.2 Faults Causing a Positive Reflection
(1) Open circuit: Open circuit means that one or both conductors of a pair
of conductors are broken or have become detached. This will cause a
positive reflection, see Fig 5.
Fig 5 Type of Fault Causing a Positive Reflection