Electrical Cable Locating
Undertaking any excavation will inevitably bring site workers into close proximity to underground utilities (i.e. electricity, gas, telecommunications, and water). Consideration should always be given to knowing the exact location of all buried utilities before and during the excavation process.
Damage to utilities will create disruption, project delays and considerable repair costs. Over half of all utility strikes are to electrical cables, with a majority caused by mini diggers, air powered tools and hand tools. This dangerous combination provides the highest risk to all teams.
To safeguard against utility strikes, a cable locator is used for detecting the presence and proximity of buried utilities.
Current supply and utility frequency
When an alternating current (AC) travels along a cable, an electromagnetic field is generated. The alternating current not only creates a magnetic field but also the oscillation of the current between positive and negative creates a frequency known as hertz (Hz).
Locating the signal
To detect the magnetic fields emitted from a buried utility, the locator uses aerials built up of wire wrapped around ferrite rods. The aerials are used to amplify the small electromagnetic signals emitted by the utility and to provide an input to the locator’s circuitry.
As the cable locator passes within close proximity to a buried utility, the interaction with the magnetic field is measured. The locator using advanced algorithms displays the reading through the user interface. The signal reading will increase as the locator moves towards the utility and decrease as the locator moves away.
A supporting audio output increases and decreases in line with the signal reading, helping to pinpoint the position of the utility.