Chauvin Arnoux LOCATO 110 Mode D'emploi page 45

2nd solution
This second solution consists of using a magnetically screened cable. On
one side the core of the cable is joined to the Emitter and the weave (iron,
steel) is connected to the battery powering the Emitter. On the other side,
core and weave are connected.
The magnetic screening of the cable has the advantage of totally isolating
the core from external fields.
Consequently, the outward and return of the pulsed current don't tend to
cancel one another and the cable can be followed throughout its route in
the pipe. When the connection point is arrived at, the detection will be
almost zero, and the user will have found the place where the pipework is
blocked.
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