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3.1.3 Finding interruptions
Must be a dead circuit
Connect adjacent lines to an auxiliary ground like in
fig. 3-1-3
Connect the "+" lead of the transmitter to the line under
test and the "-" lead to an aux.ground. like in fig. 3-1-3.
1. Ensure the ground is connected properly.
2. The transition resistance of the interruption must be higher
than 100kΩ.
3. When tracking interruptions on multi-line cables, all other
lines inside the cable's casing/conduit need to be grounded.
If not, the transmitter's signal might bleed into other
conductors and throw off the reading from the receiver.The
tracking depth for shielded or multi-line cables may differ
due to the lines wrapping around each other.
1. The auxiliary ground connected to the "-" side of the
transmitter can be the included grounded rod, the ground
line of a grounded socket, or any other apparatus that is
properly grounded.
2. The point at which the signal received by the receiver drops
abruptly will be the location of the interruption.
3. Adjust the transmitter level to compensate for differing
detection depths.
4. In manual mode, the proper sensitivity setting is crucial to
locating the interruption.
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3.1.4 Locating interruptions using two transmitters
When using the transmitter to locate an interruption in a
line, depending on the conditions, finding the interruption
can be difficult to pinpoint precisely. This problem can be
overcome with the use of two transmitters; one connected
at each end of the line and each set to a different code.
Preconditions:
CANNOT be a live circuit.
All parallel lines not used
need to be connected to
an auxiliary ground.
Connect transmitters to
opposite sides of the line
as in fig. 3-1-4.
If the transmitters are connected as
in fig. 3-1-4, the receiver will pick up
one signal on the left side of the
break and the other signal on the
right side of the break.If the receiver
is above the break, no code will be
displayed due to overlapping
signals.
1. Adjust the
transmitter level to
compensate for
differing detection
depths.
2. In manual mode, the
proper sensitivity
setting is crucial to
locating the
interruption.
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