When upgrading or repairing telecommunication and other systems, it is not always easy to find a place for the laid communications. Cable tracing is the search for the place where the cable passes.
Even if it is clearly visible, sometimes it is required to trace the location in a bunch of others. Often, documentation with gasket diagrams is missing or of poor quality.
Not every user understands cable tracing: what it is and how to produce it. In the process of performing this operation, the following tasks are solved:
- determination of the location and depth of signal and power cables;
- finding faults in the lines;
- inspection of the area before excavation to avoid damage to utilities.
Cable detector
The search for cables is carried out using devices that work on the principle of pointing the tone generator of the signal in the wires and its reception, amplification and playback through headphones or speakers.
Search where a generator with a locator is used is called active. The installer traces the route from the signal supply point along the line at the volume level. The device does not register 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 tested: underground utilities, cables in buildings, power lines, metal channels. In the arsenal of installers there is a set of devices with advanced functions, among which there is a continuity, resistance measurement, etc.
The sensor can detect fields created by other signal sources:
- power lines;
- telephone cables;
- broadcast network;
- conductive lines at 140-300 kHz.
In these cases, you can do without a generator, where the search is carried out in a passive mode.
Signal Generator Parameters
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 supplied in various ways:
- direct connection to the cores using clamps;
- coverage from the outside with an inductive clamp or clip without breaking the shell (in accessible places);
- outside of the antenna when the cable is located underground.
Typically, cable tracing is performed when it is disconnected. With a direct connection, the signal level is high. Some models may detect live lines. In this case, 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 guided into all adjacent cables. However, the usability of the method outweighs its disadvantages. Often it is used in places where direct connection is not possible. The range of the generator is limited and sometimes it is necessary to connect it several times until the track ends.
In addition, the method with an inductive antenna is used to find communications crossing the path of the main line with the transmitter. To do this, with the receivers along the cable 2 people move 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.
Instrument selection
When buying, you should select the device that is most suitable for a certain 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 contact device. In addition to sound indication, a visual one is used so that you can work in the presence of noise. Sensors are set sensitivity controls.
Special models are available for tracing aerial and coaxial cables. When buying a product, you should familiarize yourself with the instructions, which describe in detail the application methodology.
Cable tracing
Narrow specialization underground locators are common, allowing you to detect cables laid openly or in channels at a depth of 2 m. Their functions may include determining the depth and location of the closure of the braid or core to the ground. Devices are used for tracing underground or in buildings.
The cable tracing in the premises is performed by universal devices with a full set of functions. With their help, you can find the conductor under the plaster, behind the panels, in the concrete floor and behind the suspended ceiling. The signal is supplied from an inductive clamp with detection at a distance of 1.5 km. It is well recognized by ear if it consists of two alternately applied frequencies. For a whip antenna, the conductors are kept open or closed to a high resistance load. To detect a cable with a magnetic coil, its conductors are short-circuited or through a low-resistance resistor.
Communication Search Features
Cable tracing requires the development of certain skills that can detect places of open or shorted wires. By adjusting the sensitivity of the probe, the required wires are in the beam by a stronger signal. If his auditory perception is not always obtained in noisy places, a visual indicator can be used.
If the magnetic field is distorted from the action of neighboring conductors, the sensor readings may differ during repeated measurements. The adjusted value is found as an average value.
Check the depth of the track do at different distances from the ground. In this case, the obtained values should differ by the amount of probe movement.
Trace systems
Instruments for searching for underground and overhead lines should include a complete set of equipment. An example is the cts 132j cable tracing kit, designed to identify cables and pairs in telecommunication systems.
The system is used to search for underground and overhead lines and detect faults in them.
The reviews about the cts 132j cable trace device are contradictory: sometimes you have to purchase accessories additionally, which is more expensive. It is important to choose the right service.
Test Kit 701K
A cable routing kit is used to search for wires on a line or in bundles, to determine gaps 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 a sound and visual indication of the signal. Modernization of the device is a set of 711K, where 3 sound signals are added .
Cable Management Kit TEMPO CTS 132j
The system includes a tone generator with a varying frequency of the supplied signal. A coil is used to detect the magnetic field, and an inductive probe is used for the electric field. In the first case, a strong signal is obtained by closing the pair at the far end, and in the second, it is open. The presence of an outer foil sheath shields the electric field, but the magnetic is easily detected. When tracing a cable, the signal can be fed through a 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, provides the determination of the necessary conductors in the bundles, identifies defects. Analog mode is also allowed.
Set of cable tracing MT 8200 60A
The system makes it possible to search for telephone, coaxial cables, twisted pairs, other types for security systems and television. There is also the use of digital signals that reduce the influence of pickups.
Optical cable search
Fiber optic cable may contain metal elements. Here they should be used similar to the screen of a conventional wire. The optical cable is traced by connecting the generator to the metal sheath in any known manner, after which you can search using the probe.
If the cable does not contain metal elements, it is marked during installation. To do this, a resonant circuit from an inductive coil and 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. So is the location of the line.
Conclusion
Tracing allows you to determine the direction and location of hidden extended objects, mainly cables. It is important to correctly adjust the volume level of the signal on the transmitter and receiver. Particular attention is paid to the places of its sharp change. This can be interference from metal parts underground, branching, change of direction, cable termination, change in depth, the appearance of a conductor located nearby in parallel.