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5.7.3
Blind Search, Metal Mass Location, Ground Survey with the Carrying
Handle
A "blind search" is a search for the location of a conductor with an unknown source or ending.
The VM-480B must be operated in the Inductive Mode using a systematic grid approach. Looking
for a "metal mass", such as a manhole cover or steel drum is the same as a "blind search" with
the exception that the search paths need to be closer together so as not to miss the metal object.
A "ground survey" is a process by which an operator can locate all the underground conductors
within a particular area.
5.8 Conductor Identification Using a Second 4820 Metroclamp
When exposed multiple conductors are present, for example in conduits, ducts, or pedestals, use
the method described below to identify a specific conductor.
1. Apply transmitter signal to the target conductor using a 4820 Metroclamp, as described in
Section 4.2.
2. Plug a second Metroclamp cable into the jack marked AUX INPUT on the receiver.
3. Set the RANGE switch on the receiver to "Norm". Set the MODE switch to "Active".
4. Place the Metroclamp around each conductor in succession, making sure that the jaws are
fully closed. The conductor with the highest field strength indication is the target conductor.
See below graphic.
NOTE
This method will work only if there is no cross bonding on the length of the
conductor between the conductor and the receiver.
Position of Metroclamps When Using Two
1 Receiver
2 Transmitter
5 Operation
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