Finding Breaks/Opens; Finding Shorts - Amprobe AT-8000 Serie Manual De Usuario

4. SPECIAL APPLICATIONS

4.2 Finding Breaks/Opens

It is possible to pinpoint the exact location where a wire is broken, even if the wire is
located behind walls, floors or ceilings.
1. Make sure that wire is De-energized.
2. Use the steps described in section 3.2 to connect the Transmitter and perform tracing
with the Receiver set to De-energized TIP SENSOR mode.
3. For best results, ground all De-energized wires that run in parallel with the black test lead.
(Figure 4.2).
The tracing signal generated by the Transmitter is conducted along the wire as long as there is
continuity in the metal conductor. To find a fault, trace the wire until the signal stops. To verify
the fault's location, move the Transmitter to the other end of the wire and repeat, tracing from
the opposite end. If signal stops at the exact same location, the fault has been located.
Note: If the place of the fault is not found, the result may be a high resistance break
(partially open circuit). Such a break would stop higher currents from flowing but will
conduct the tracing signal through the break. Such faults will not be detected until the wire
is completely open.

4.3 Finding Shorts

Shorted wires will cause a breaker/fuse to trip. To correct this, disconnect the wires and
make sure the ends of the wires on both sides of the cable are isolated from each other and
other wires or loads and are De-energized.
1. Connect the Transmitter with the test leads to the circuit as shown in Figure 4.3.
2. Turn the Transmitter to Loop mode by pressing HIGH button for two seconds. Verify
that the Loop LED is ON.
3. Set the Receiver to Energized TIP SENSOR mode (the Transmitter will generate safe low
voltage tracing signal) and perform tracing.
Start tracing the cable until the signal stops. To verify the place of the fault, move the
Transmitter to the other end of the wire and repeat tracing from the opposite end. If the
signal stops at the exact same location the fault has been located.
Note: This method will be affected by signal cancellation effect. Expect a relatively weak signal.
Figure 4.2: Locating the place of the fault
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