What is cable tracing?

2024 Author: Howard Calhoun | [email protected]. Last modified: 2023-12-17 10:16

When modernizing or repairing telecommunications and other systems, it is not always easy to find the location of the laid communications. Cable tracing is about finding where the last one goes.

Even if it is clearly visible, sometimes you need to trace the location in the bundle of others. Often documentation with wiring diagrams is missing or of poor quality.

Not every user understands cable tracing: what it is and how to produce it. During this operation, the following tasks are solved:

• determining the location and depth of signal and power cables;
• finding line faults;
• survey the area before earthworks to avoid damage to utilities.

The principle of the cable locator

Searching for cables is done using devices that work on the principle of pointing a signal in the wires with a tone generator and its reception, amplification and playback through headphones or speakers.

Search,where a generator with a trace finder is used is called active. The installer traces the route from the place where the signal was given along the line according to the volume level. The device registers not the conductor itself, but the electromagnetic field created in it by the induced signal.

First of all, the sensor with the generator are selected with the same parameters - corresponding to the type of lines being checked: underground utilities, cables in buildings, power lines, metal channels. In the arsenal of installers there is a set of devices with advanced functions, including continuity, resistance measurement, etc.

The sensor can detect fields generated by other signal sources:

• field lines;
• telephone cables;
• radio broadcast networks;
• conducting lines on 140-300 kHz.

In these cases, you can do without a generator, where the search is carried out in a passive mode.

Parameters of signal generators

The main parameters are the power and frequency of the induced signal, which can be constant or in the form of several alternating (up to four) values of 0.2-130 kHz. The signal is given in different ways:

• direct connection to cores with clamps;
• covering from the outside with an inductive collar or clip without breaking the sheath (in accessible places);
• outside the antenna when the cable is underground.

Usually, a cable is traced when it is disconnected. When connected directly, the signal level is high. Some models can detect lines,under tension. In this case, a direct connection is not possible. To eliminate interference from power lines, filters are used that do not pass the frequency of 50 Hz.

The disadvantage of using inductive antennas is that the signal is directed to all nearby cables. However, the ease of use of the method outweighs its disadvantages. It is often used in places where a direct connection is not possible. The generator coverage area is limited and sometimes you have to connect it several times until the track ends.

In addition, the method with an inductive antenna is used to find communications that intersect the path of the main line with the transmitter. To do this, 2 people move along the cable with receivers at a distance of 20 m.

In addition to the antenna, other inductive interface devices are used that do not need to be connected to conductors. In this case, the signal is applied to only one cable.

Choice of fixtures

When buying, you should select the device that is most suitable for a particular type of work. The main element of the inductive probe is a sensor in the form of an antenna (pin or magnetic) of a combined device or a contact device. In addition to sound indication, visual indication is used so that it is possible to work in the presence of noise. Sensitivity controls are installed in the probes.

Special models available for routing overhead and coax cables. When buying a product, you should read the instructions, which describe in detail the method of application.

Cable routing

Spread undergroundhighly specialized locators that allow detecting cables laid openly or in channels at a depth of up to 2 m. Their functions may include determining the depth of occurrence and the location of the short circuit of the braid or core to the ground. Devices are used for tracing underground or in buildings.

Cable tracing in the premises is carried out by universal devices with a full range of functions. They can detect conductors under plaster, behind panels, in concrete floors and behind suspended ceilings. The signal is given from an inductive collar with detection at a distance of 1.5 km. It is well recognized by ear if it consists of two alternately supplied frequencies. For a whip antenna, the wires are kept open or shorted to a high-impedance load. To detect a cable with a magnetic coil, its conductors are short-circuited or through a low-resistance resistor.

Features of the search for communications

Cable tracing requires the development of certain skills that allow you to detect breaks or short circuits in the cores. By adjusting the sensitivity of the probe, the desired wires are in the bundle at a stronger signal. If his auditory perception does not always work in noisy places, a visual indicator can be used.

When the magnetic field is distorted by the action of adjacent conductors, the sensor readings may differ during repeated measurements. The refined value is found as an average value.

Checking the depth of the route is done at different distances from the ground. In this case, the obtained values \u200b\u200bshould differ by the amount of movement of the probe.

Systemstraces

Devices for searching underground and overhead lines must include a complete set of equipment. An example is the cts 132j cable tracing kit for cable and pair identification in telecom applications.

The system is used to search for underground and overhead lines and detect faults in them.

Reviews about the cts 132j cable tracing device are contradictory: sometimes you have to purchase additional accessories, which is more expensive. It is important to choose the right service here.

701K test kit

The cable tracing kit is used to find wires on a line or in bundles, identify breaks and short circuits.

The main elements are a tone generator and an inductive probe. The device works with any wiring: single conductors, twisted pairs, coaxial cables. There is an audible and visual signal indication. The upgrade of the device is the 711K kit, where 3 beeps have been added.

Cable Tracing Kit TEMPO CTS 132j

The system includes a tone signal generator with varying the frequency of the applied signal. A coil is used to detect the magnetic field, and an inductive probe is used to detect the electric field. In the first case, a strong signal is obtained by closing the pair at the far end, and in the second case, it is open. The presence of an outer foil sheath shields the electric field, but the magnetic field is easilyis found. When tracing a cable, the signal can be fed through the shielding braid. The kit is designed to find pairs in couplings, search for wires on lines and in switch cabinets, detect short circuits and breaks.

IntelliTone Tracing Kit

The kit is designed to track and locate cables in active networks. The generation of digital signals eliminates the guidance of extraneous signals, ensures the determination of the necessary cores in bundles, and determines defects. Analog mode is also allowed.

Set for cable tracing MT 8200 60A

The system makes it possible to search for telephone, coaxial cables, twisted pairs, and other types for security systems and television. There is also the use of digital signals that reduce the effect of interference.

Finding an optical cable

Fiber optic cable may contain metal. Here you should use them similarly to the screen of a conventional wire. An optical cable is traced by connecting the generator to a metal sheath in any known way, after which you can search using a probe.

If the cable does not contain metal elements, it is marked during laying. To do this, a resonant circuit of an inductive coil and a capacitor is installed on the cable. The so-called passive cable marker, which does not require power, receives and reflects the signal from the emitter. This is how the place isline location.

Conclusion

Trace allows you to determine the direction and location of hidden extended objects, mainly cables. It is important to correctly set the signal volume level on the transmitter and receiver. Particular attention is drawn to the places of its sharp change. These can be pickups from metal parts underground, the formation of branches, a change in direction, the end of a cable, a change in the depth of occurrence, the appearance of a parallel conductor nearby.