Cable fault locating; Know the tools to help out with underground cable faults

Cable fault locating can be quite challenging even though there is a number of fault locating techniques and quite a few tools to help out with underground cable faults. Most of these issues are due to technicians not properly interpreting the test results and then selecting the wrong tool for the task at hand, and ultimately a lot of wasted time is due to taking a shortcut in the process.

The challenges of underground fault locating may be minimized significantly by understanding the equipment and techniques available. Education and experience in cable fault locating will help correct and make improvements in interpreting of the results and definitely will help correct and make improvements in the selection of which equipment and technique is most appropriate for a particular task. However, only a high level of awareness is going to correct wasted time that is afforded through taking shortcuts. Cable fault locating can be quite challenging even though there is a number of fault locating techniques and quite a few tools to help out with underground cable faults.

Most of these issues are due to technicians not properly interpreting the test results and then selecting the wrong tool for the task at hand, and ultimately a lot of wasted time is due to taking a shortcut in the process. The challenges of underground fault locating may be minimized significantly by understanding the equipment and techniques available. Education and experience in cable fault locating will help correct and make improvements in interpreting of the results and definitely will help correct and make improvements in the selection of which equipment and technique is most appropriate for a particular task. However, only a high level of awareness is going to correct wasted time that is afforded through taking shortcuts.

The Basics of Pulse Echo

The pulse echo technique is performed with a time domain reflectometer (TDR), which combines a transmitter and a receiver. The transmitter sends out a low voltage high frequency pulse of a short duration onto a cable. This pulse of energy travels along the surface of the cable until it encounters some type of disruption manifested in a change within the characteristic impedance of the cable; these mismatches in the characteristic impedance of the cable may be caused by the start of the cable, splices in the cable, transformers, faults, etc. Depending upon the magnitude of the impedance change, either part or all of the transmitted energy reflects and travels back to the time domain reflectometer. In essence, this technique creates an electronic or a graphical roadmap of the underground cable showing different events along that path.