78-8130-6151-8 Rev G
35
12. Locating Buried Sheath Faults And Earth
Return Faults
(3M
™
Dynatel
™
Models 2273ME and 2273ME-iD only.)
Note: Remove (disconnect) both the near-end and far-end grounding from the test
section. Fault location will not work unless the near-end and far-end grounds are
disconnected.
Note: This method only works on direct buried cables/conductors. It will not work if
the cables/conductors are faulted inside of a conduit, such as a PVC conduit.
A. Transmitter Setup
Note: Do not make any connections while the transmitter is on.
1. Attach the red clip to the earth-faulted conductor of the cable or conductor under test.
2. Place the ground rod behind the transmitter and in parallel with the target path.
3. Connect the black clip to the ground rod behind the transmitter and in parallel with
the target path.
4. Press and hold
off
[T-1] to perform a battery test.
5. Press
on: Ohm-meter/Fault Locate/Tone
[T-2] to turn the transmitter on.
−
The resistance of the fault will be displayed in ohms on the transmitter Digital
Display [T-4].
− Resistance less than 50KΩ = Significant fault exists.
− Resistance 50KΩ to 1.0MΩ = High resistance fault exists (May or may not
cause problems yet, but gets worse with time.)
− Resistance greater than 1.0MΩ = No significant fault exists.
Note: The fault locating limit is 2.0M
Ω
, although the transmitter's ohm-meter mode
can display a fault resistance up to 10M
Ω.
6. Press
on: Ohm-meter/Fault Locate/Tone
[T-2] again, to select Fault mode.
−
The flag will turn on under the fault icon in the display (as shown in illustration
below).
B. Pinpointing the Buried Fault
1. Connect the 3M™ Earth Contact Frame (also known as an A-Frame) to the
External Jack
[14] ([13] on 2250M Receiver) of the receiver using the Earth
Contact Frame cable (1.2 m (4 ft.) cable).
2. Press
On/Off (Power)
[1] to power on the receiver. The receiver display screen will
display
"Fault Calibrating"
for about 5 seconds.
