3M CablePipe Locating Techniques Manual

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August 1998
80-6108-6216-3-C
Cable and Pipe Locating
Techniques
for use with 3Mª Dynatelª
Cable and Pipe Locators 

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Table of Contents
Section 1 The Basics of Cable Locating
1. Introduction ........................................................................................................................... 7
2. Applying the Signal: The Direct Connect Method ................................................................. 8
3. Applying the Signal:  The Induction Method ......................................................................... 9
4. Applying the Signal: The Dyna-Coupler Method...

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4. Applying Signal to Power Cables: Dyna-Coupler Method .................................................. 33
A. Applying Signal to Primary Cables ................................................................................ 33
B. Applying Signal to Secondary Cables ........................................................................... 34
5. Identifying Slack Loops .......................................................................................................35
6. Identifying A Cable...

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This manual has been prepared to provide the most important written instruction material to date for
cable locating with 3MÕs Cable and fault Locating products.  It assumes a basic understanding of the
commonly used terms in telephone transmission and switching.  Whenever this manual is reissued, the
reason(s) for reissue will be listed here.  Comments concerning the contents or organization of this
document, as well as suggestions for improvement are welcomed.
3M Telecom Systems Division
Lab -...

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Section 1 The Basics of Cable Locating
1. Introduction
1.1 Cable locating is not an exact science, yet. To do a good job, you must know your equipment, and
use your intuition and good judgment.  Certain techniques can alert you to potential problems and
make the difference between a good locate and a bad one. In this manual, we discuss the basics of
locating buried cable or pipe by using a Transmitter to apply a signal to the conductor, and tracing
the conductorÕs path using a Receiver.
1.2 There are...

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2. Applying the Signal: The Direct-connect Method
2.1 Connecting directly to the cable or pipe you want to trace (power cables only if they can be de-
energized) is the most accurate method of cable locating. Connecting the Transmitter directly
isolates the signal to one cable.
Danger! Voltage greater than 240 volts will damage equipment and cause personal injury and death.  Make all
direct test connections before turning on the Transmitter.   Then activate the Transmitter in the Ohms
mode and check...

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3. Applying the Signal:  The Induction Method
3.1 The simplest way to put signal on a buried cable or pipe is with induction, where you merely set
the Transmitter on the ground directly over the cable and turn the Transmitter on. The Transmitter
induces signal current (tone) into any parallel conductor within range.
3.2 It is important to place the unit directly over the cable, with the hinge parallel to the cable path, as
shown above. The signal drops off rapidly if you place the Transmitter even 5 or...

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4.1 The easiest way to put signal on a cable is with the Dyna-Coupler. When its jaws close around a
cable or pipe, the Dyna-Coupler couples the Transmitter signal onto it. As with the other methods,
the cable or pipe must be grounded to form a complete circuit path for the signal to follow.
4.2 When you apply the Dyna-Coupler between grounds, signal will be on the section between the
grounds.
4.3 You can find detailed instructions for using the Dyna-Coupler in your application in later sections
of...