How to find a fault

Follow Avatar Anthony Caplin
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Starting from the transmitter, walk along the cable or pipe route pushing the A-Frame spikes into the ground with the green spike pointing away from the transmitter. Where there are no faults the dB reading will be low and the direction arrow may flicker forward and back.

NOTE: Flickering arrows may also indicate that you may be too far away from the fault or ground stake (or both) for the locator to lock on.

 

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Cable sheath fault-finding

 

If you are trying to locate high resistance faults or there is a long distance between faults, carry on with the survey and the locator will lock on when you get closer to the fault.

 

Locating faults with the locator and A-frame

 

Take readings at the survey intervals determined by the reference reading.

To locate the cable or pipe while using the fault find signal during a Fault-Find survey, press the antenna key.png key once and the locator will switch to Peak locate mode. To use alternative antenna modes, press the antenna key.png key to step through available antenna modes. To get back to fault find mode step through all available antenna modes until the locator goes back to fault find mode.

NOTE: While the A-Frame is connected to the locator, depth and current measurements will not be available. If depth or current measurements are required, remove the A-Frame lead from the locator.

As a fault is approached the Fault-Find direction arrow will lock on to the fault signal, point forward and the dB readings will increase. When the fault is passed the arrow will point back towards the transmitter. Take readings at smaller survey intervals to determine the exact point of the fault.

When the A-frame is directly over the fault the dB reading will drop. 

NOTE: The values given are for illustration purposes only and may not be the same as those obtained in other situations.

To pinpoint the fault, turn the A-frame 90° to the cable or pipe and Fault-Find until the exact point is found. Where the arrow direction changes the center line of the A-frame is now directly over the fault.

Mark the ground to show the position of the fault. Find the maximum dB reading in front of the fault by pushing the A-frame into the ground at small intervals. Note the dB reading. If the reading is approximately the same as the reference reading, you can assume that there is only one fault. If the reading is less than the reference reading, keep surveying the cable for other faults.

NOTE: If the cable or pipe runs under a road, use the equipment as normal on the road surface as it can sometimes detect signals when working on blacktop, concrete, or paved surfaces. If necessary, try wetting the road surface. Pouring a very small amount of water around the bottom of the A-frame spikes before each Fault-Find will generally ensure a good ground connection.

NOTE: If the cable or pipe runs under a paved surface, the fault can often be pinpointed by fault finding in the grass / soil adjacent to the paving. Reduce the distance between placing the A-frame spikes in the ground to allow for the increased distance to the actual fault position.