40 78-9000-0192-2 Rev C
B. Pinpointing the Buried Fault
Step 1. Connect the 3M™ Earth Contact Frame to the External Jack [15] ([14] for 2550) of
the receiver using the Earth Contact Frame cable (4 ft. (1.2 m) cable).
Step 2. Press On/Off [1] to power on the receiver. The receiver display screen will
display "Fauly Calibrating" for about 5 seconds.
Step 3. Press Menu/OK [5].
Step 4. Press Fault [SK] to select Fault mode.
Step 5. Hold the receiver in one hand and the Earth Contact Frame in the other with the
solid green-banded leg of the frame toward the test section. Near the location
of the ground rod (about one Earth Contact Frame width away from the ground
rod, slightly to the side and towards the faulted cable.), insert the Earth Contact
Frame probes fully into the ground in line with the target path.
Step 6. Press REF [SK] to record the fault Signal Strength [9] ([8] for 2550 locator)
level reference. The signal level will be recorded in the box above REF [SK]
on the display. This reference indicates the Signal Strength [9] ([8]) for 2550
locator) level at the ground rod. When the operator reaches the major fault
location, the Signal Strength [9] ([8]) for 2550 locator) indicated on the receiver
will be very close (within 12dB) to this reference signal strength level.
Step 7. Continue along the cable path, re-inserting the Earth Contact Frame probes
every few steps while watching the receiver bar graph. The bar graph on the
receiver will fill toward the right side of the display (green Fault Finding
Direction Indicator [8] (See illustration below)), indicating that the fault is
ahead of the operator (in the direction of the green-banded leg of the Earth
Contact Frame).
Move in direction of red-banded leg
of 3M™ Earth Contact Frame.
Move in direction of green-banded leg
of 3M™ Earth Contact Frame.
Transmitter Signal
Green Band Red-and-White-Striped Band
Ground Fault location