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Advanced Underground Utility Locating

Fault Locating & Detection

Electrical lines can experience faults due to a variety of reasons. A fault in an electrical line refers to any abnormal condition that disrupts the normal flow of electricity and can potentially lead to dangerous situations, including electrical fires, equipment damage, and electrical shocks. Some common causes of electrical line faults include:


  • Physical Damage: Physical damage caused by construction equipment, digging, excavation, vehicle collisions, or even vandalism can lead to electrical line faults. When the protective insulation of the wires is compromised, it can result in short circuits or open circuits

  • Weather Conditions: Adverse weather conditions such as lightning strikes, heavy winds, ice, snow, and heavy rain can cause electrical line faults. Lightning strikes can induce high voltage surges that damage equipment and cause line faults.

  • Tree Contact: Trees or branches coming into contact with power lines can cause line faults. This contact can create short circuits or open circuits, especially during windy conditions.

  • Aging Infrastructure: Over time, the components of electrical lines, including insulators, cables, and connectors, can deteriorate due to factors like exposure to environmental elements, temperature changes, and vibrations. This aging can lead to faults.

  • Corrosion: Corrosion of conductors, connectors, and other components due to exposure to moisture, chemicals, and other environmental factors can weaken the integrity of the electrical line and lead to faults.

Advanced Underground Utility Locating
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Advanced Underground Utility Locating
  • Equipment Failure: Malfunctioning or faulty equipment, such as transformers, circuit breakers, fuses, and switches, can cause faults in the electrical system. These failures can create abnormal conditions like short circuits.

  • Overloads and Overcurrents: When an excessive amount of current flows through a circuit due to an overload or an overcurrent condition, it can cause overheating and damage to the electrical components, leading to faults.

  • Ground Faults: Ground faults occur when an unintended path to the ground is created in the electrical system. This can happen due to damaged insulation, faulty wiring, or equipment malfunctions. Ground faults can be dangerous, potentially causing electrical shocks and fires.

  • Animal Interference: Animals, such as birds, rodents, and insects, can come into contact with electrical equipment and lines, causing short circuits or other faults.

  • Human Error: Incorrect installation, maintenance, or repairs performed by unqualified individuals can introduce faults in the electrical system. Mistakes like improper connections or inadequate insulation can lead to faults.

  • Power Surges: Sudden and significant increases in voltage, often caused by lightning, switching operations, or faults in the power grid, can lead to electrical line faults.

  • Manufacturing Defects: Poorly manufactured or substandard electrical components can have defects that result in premature failures and faults.

Preventing electrical line faults involves regular maintenance, proper installation, adherence to safety protocols, and the use of high-quality components. Detection and repair of faults are essential to maintaining a safe and reliable electrical system.

Most common faults come from previous excavation hits during digging that were not repaired correctly, and often happen months if not years after something has been hit. Our longest hit to fault that we have seen has been 20 years. 

Fault Locating & Detection

How do we find your fault? 

AUUL uses a variety of methods when fault locating, Including the use of Mulitmeters, Rd8100, RD8100 A frame attachments and other tools to assist in detection of a fault.

The type of fault will vary, some or completely open, some are shorted or a combination of both. Each fault is different and  takes different methods to detect. Most fault finding systems have a way of transmitting a DC voltage from the transmitter down the faulted line or lines and use the revicer with the a frame to pinpoint the location of the fault. The A- frame along with the RD locator use this signal to detect where the signal is going to ground,  if you can imagine a leaking water line and the water coming out of the ground would be similar to how fault locating equipment detects where that signal is coming off the wire into the ground. 

We can find faults on all kinds of wires, lighting, pool wires, wires going to a well house, or  to a well head, wires from panels to outbuildings, main line faults from meters to transformers, from pole meters to a residence or buildings, from building panels to other buildings.

Where we can not find a fault or where it will  be extremely difficult to do so would be lines that are inside conduits or duct banks. These conduits prevent the transmission of signal from our transmitters from going to earth or ground, preventing the signal from reaching our devices. However if the conduit is 3 inches or greater in size and has room we can stick a camera down the pipe and visually inspect for a fault. But be aware that at this point we might not be able to find the fault and the line might need to be fully replaced.   

Advanced Underground Utility Locating
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Advanced Underground Utility Locating

In the instances of conduits were me might be able to detect a signal, that signal could come from either water escaping from a conduit that is going to ground through a joint in the conduit or a broken conduit that has been damaged by digging, rodents or other means and the signal is going to ground. In the case of a joint fault, an area of the fault might be detectable but not the exact location. 

Some lines have multiple faults, where one fault is detected repaired and another fault is found after the fact, it is very frustrating, but it does happen. Typically multi-faults happen once one fault is detected because either insulation on wire has weakened, wire was pulled incorrectly or multiple excavation hits on a single line. Sometimes faults when they trigger even cause other faults because of the serge of electricity through a line. 

The signal emitted from these devices will go directly to the nearest ground, so proper setup is important to ensure that all other possible paths to ground are eliminated other than the fault.

For this reason all legs of a wire, the positive, negative and neutral must be removed from the meter base and from the transformer and open/ in the air. 

This would also include lines that feed multiple buildings off of one line from a junction box, where a main feed comes from a transformer or even from a meter to a junction box and provides power to multiple structures onsite. That junction box or the other panels connected to the junction box would also need to have all three legs of the wires removed. Some buildings even “daisy-chain” power supplies such as apartment complexes or trailer parks. 

Fault Locating & Detection

Here are the steps to have in place before we come to locate your fault:

  1. (main feed fault) If it is a fault from the transformer directly to the meter base at your house you will need to call and schedule a disconnect from the transformer before you do anything else this disconnect is from your power provider. PSE, Tacoma power, Peninsula light, SPU, or other providers, find your power bill to find who you should call.

  2. If the fault is from your panel to an outbuilding or from a meter on a pole to your house shut power off at the meter and disconnect all three legs coming from the meter to your house or going from the panel to your house to the outbuilding, We recommend always calling an electrician to do this safely as electricity can kill you.

  3. (main feed fault) Have an licensed electrician disconnect the three legs of your wire from your meter base, it is possible for homeowners to do this step however electricity can kill you and it is not recommended unless you have significant experience working with electrical as an arc flash caused by touching live cables, capacitors that exist in your home that hold a charge, or backfeeding from other sources of power generators being one, could be fatal. 

  4. Once all wires are “free” and disconnected from the panel/meter/transformer we will locate the line, provide depths on the line and start detecting the fault along the line.   

In rare cases or cases of emergency fault locating needs, we can perform a live fault locate, results of a live fault locate are not guaranteed as we use less precise equipment and is more successful if a line is closer to the surface, the ground is wet, the wire is not in conduit and the line path is not under concrete, rock, asphalt/hard surface.    

Advanced Underground Utility Locating
Advanced Underground Utility Locating

If We Can't Find It, It Can't Be Found. Contact an office near you to get a free quote. 

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