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It's a Jungle out there. Underground Utility Detection & Inspection Services

Understanding Ground Fault Detection/Locating Services


The outcomes of a ground fault can be devastating. However, there are some things we can do to prepare and prevent them. Are you also wondering what precisely is a ground fault and what is the reason behind its occurrence? Well, a ground fault appears when electricity unexpectedly travels to the ground. The current substantially increases and causes the breaker to trip. A ground fault can be caused by damage to a wire, damaged appliances, incorrect wiring, worn wire insulation, etc. When these issues occur, you should determine if you will need ground fault locating services.

Understanding Grounding First

To understand what a ground fault is, it is vital to gain insights into the workings of an electrical circuit. When we dive into how a circuit precisely works, we know a hot and a neutral wire is connected to devices, and then the flow of electricity takes place from the source to the load and back again continuously. After this, an additional grounding wire gets connected to the earth with the device’s assistance, through a grounding rod, or other types of grounding methods. Most individuals may believe that the grounding wire is useless and may feel that there is no use for a grounding wire. But once a ground fault arises, the grounding wire saves your day, and you will not regret having a backup plan anymore. 

Before grounding wires were used, people used to experience unexpected shocks after touching a malfunctioned electrical device by mistake. The electrical current surged rapidly, but since it had no particular path to go, it traveled through the person who came in contact with it and sent it to the ground. Now that, additional grounding wires provide a path for any escaping electricity to travel to the ground. It assists in protecting individuals and buildings alike to avoid shocks and prevent their structures from catching fire or damage.

What Precisely is a Ground Fault?

A ground fault occurs when electricity has an unforeseen path to the ground. The path to ground is resistance free and unrestricted and consequently assists the flow of charge to increase extraordinarily and rapidly. Ground faults bring the most threats and dangers to areas that experience high moisture. Occasionally, the chosen path to the ground could be the outside of an appliance, and when someone touches it, an electrical shock can occur. While shocks are the most common danger, fires, burns, and power outages can also occur, causing a threat. To prevent such hazards, we suggest hiring a ground fault detection expert like CNI Locates to save time, money, and help keep you and your property safe. 

Differences Between a Short Circuit and a Ground Fault

A short circuit is completely different from a ground fault, and individuals who work with electricity daily can easily navigate the common differences between them. Below are some things that a ground fault and a short circuit have in common:

  • Both can cause unexpected dangers and result in unexpected shocks and fire hazards. 
  • Both originate from the flow of electric charge to the unplanned path outside of the circuit. 
  • Both result from an uncontrolled increase in electric flow, from experiencing a substantial change in resistance.
  • Both cause tripping of breakers and interruption in the smooth flow of power. 

Though many people consider a ground fault to be a type of short circuit, they are not necessarily the same. While the electric current quickly chooses an alternative path to reach back the source on a short circuit, in a ground fault, the electric current seeks the most accessible way to reach the ground. Therefore, you can always connect with our professionals at CNI Locates for budget-friendly and trusted ground fault detection services in Oregon and Washington State.

Tips for Ground Fault Detection Services

If you have direct buried cables or wires, the possibility of a ground fault occurrence is significant. But what should be your first action when you have a cable or wire that fails? You can contact CNI Locates to identify the location of your ground fault in Oregon or Washington State within 24 hours’ notice, Monday through Friday. We have field offices in Eugene, OR, Portland, OR, Everett, WA, Renton, WA, Seattle, WA, and Tacoma, WA.

If you have a damaged direct buried wire or cable (not in conduit), do not dig until you know the exact location where it is damaged. It can cause expensive, frustrating, and hazardous issues if you do not locate the fault and utilities around it first.

Fault Detection

How Does Ground Fault Detection Work?

CNI Locates can save you time and money by identifying where your wire is damaged or has failed. Additionally, we are known for offering the most trusted and reliable ground fault locating services in Oregon and Washington. Our expert technicians use A-frame fault finders to locate the location(s) that need to be repaired. CNI Locates is capable of locating cable-to-ground faults caused by damaged cable sheaths and can also locate damage to insulation on pipelines. This technique is known as Fault-Finding and uses specific fault-find signals (8K FF) that are transmitted through the cable, pipeline, or wire in question.

Fault-find signals can only be applied using a Direct Connection method with test leads.

The A-frame accessory is used to locate cable sheath faults on power or telecom cables and insulation faults on pipelines.

How An A-frame Fault Finder works:

  • It applies an 8K FF (Fault Find) frequency to the power, telecom cable, or pipeline in question.
  • The Fault-Find direction arrow locks onto the fault signal and points forward, increasing the dB readings as the fault is approached.
  • The arrow will point back toward the transmitter once the fault is passed.
  • Readings are taken at smaller survey intervals to precisely determine the point of the fault.

Preparing the Line

  • Locate the complete path of the utility to know its exact pathway.
  • Identify which wires are faulted by performing a resistance test (ohm test) on each wire.
  • Disconnect all wires, including the hots, neutral, and ground, from each side of the wires (During the fault-finding survey, remove all earth bonds from the line being traced).
  • If there are any earth bonds along the path of the fault to find the signal, it may direct the user to that location as that will be the preferred path for the fault to find a signal to the ground and may result in the fault not being located accurately.

Connecting the transmitter

  1. Connect the direct connection test leads to the transmitter accessory socket with the transmitter switched off.
  2. Clip the red connection test lead to the cable, cable sheath, pipe, or wire confirming that the area around the connection is clean and that a positive connection is attained.
  3. Extend the black connection lead as far away as possible at 90° from the apparent route of the target and clip the connector to the ground stake, confirming that a positive connection is attained.
  4. Always connect the black connection test lead to a ground stake and not a pipe, fence, wire, or buried cable, as these may carry the signal.

Reference readings

Before identifying a fault on a target, it is good practice to acquire a reference reading from the ground stake. Reference readings help provide the information below:

  • Severity of fault
  • Survey interval (distance between reference readings)

Before taking the reference reading, set up the transmitter and receiver using the following instructions.

On the transmitter:

  1. Select a fault-finding frequency.
  2. Increase or decrease the output signal level (as needed).
  3. If necessary, you can increase the output if the fault is located on a high-resistance target or if the target is long.

Warning– The transmitter will be able to output high voltages when selecting 8KFF and a high voltage warning icon will appear on the transmitter’s display.

On the receiver:
  1. Connect one end of the connection lead to the receiver and the other end to the A-frame socket.
  2. The locator will automatically recognize the A-frame and display the A-frame icon on the display.
  3. Select a fault-finding frequency (8K FF).
Obtaining a reference reading:
  • Position the A-frame roughly two yards (six feet) from the ground stake and push the A-frame spikes into the ground with the green spike towards the ground stake. Attach the receiver to the A-frame by the retention hook. (Make sure the receiver is in line with the A-frame and that the receiver is positioned towards the green spike, if you are holding the receiver separately.) The fault direction arrow should be pointing away from the ground stake. If it isn’t, ensure the transmitter and test leads are connected correctly (red clip to the target and black clip to the ground stake). Take the dB reading approximately two yards (six feet) away from the ground stake and keep it for reference. If there is a single fault on the cable, it will be approximately the same dB value as the reference reading.
  • To establish how often to take references on the target, move away from the ground stake and take further readings until the arrow has difficulty in locking and the dB reading is low. Measure that distance between the A-frame and the ground stake. This is the distance you can safely use between taking readings on the cable, pipe, or wires to ensure that you don’t miss the fault.
  • 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. The dB reading will be low where there are no faults, and the direction arrow may flicker forward and back.
  • Flickering arrows may imply that you are too far from the fault or ground stake (or both) for the locator to lock on.
  • If there is a long distance between faults or if you are trying to locate high resistance faults, continue with the survey, and the locator will lock on when you get closer to the fault. Take readings at the survey intervals determined by the reference reading. 
  • You will observe the Fault-Find direction arrow, pointing forward, and increased dB readings as a fault is approached; the arrow will point back toward the transmitter when the fault is passed. Taking readings at smaller survey intervals can assist you with determining the exact point of the fault.
  • When the A-frame is directly over the fault, the dB reading will drop as shown opposite.
  • To pinpoint the fault, turn the A-frame 90° to the target and Fault-Find until the exact point of the fault is identified. Where the arrow direction changes, the center line of the A-frame is now directly over the fault.
  • CNI Locates will mark the surface to show the location 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 dB reading is roughly the same as the reference reading, you can presume that there is only one fault. If the reading is less than the reference reading, continue surveying the target for other faults.

Possible Limitations

  • Multiple Faults. Typically, we can accurately test up to one fault from each side. If there are more than two faults, we may need the client to expose and cut the wires after the fault to test for another fault. 
  • Wet the surface to ensure a good ground connection and pour water onto an industrial sponge around the bottom of the A-frame spikes before taking each reference, if the cable runs under a road, blacktop, concrete, or any paved surfaces.
  • If the target runs under a paved surface or building, the fault can often be identified by fault finding in the grass/soil adjacent to the paved surface or building. (If possible, reduce the distance between placing the A-frame spikes in the ground to allow for the increased distance to the actual fault location.)

The A-frame fault finder assists in indicating the severity of the ground fault and permits our expert technicians to find its location. This allows us to identify the fault that is causing problems in your system. By the time we are done using our fault detection and locating services, you will know the exact location where you need to make your repair(s). 

Common Dangers of Ground Faults

Below are common hazards that can occur due to a ground fault:

  • Electrical Shock: An electric shock is viewed as the biggest and most common danger, specifically in areas that are prone to moisture.
  • Damage to Appliances: This can happen when a sudden surge of electricity is generated due to a ground fault, causing damage to appliances that are connected to that circuit, panel, or meter.
  • Power Outages: Power outages from ground faults can cause you to be without power for days and sometimes weeks. This can be life threatening if there is medical equipment that needs to operate with electricity. It can also be dangerous by causing food to spoil and heat to drop, among other issues that are related to losing power.
  • Fire: The uncontrolled surge of electricity can generate heat, start a fire, and cause a catastrophe.
  • Burns: Due to the heat generation from the increase in electricity flow, individuals may come in direct contact with extremely hot wires or appliances, resulting in severe burns.

Explore The Common Causes of Ground Faults

  • Water, a common conductor of electricity, leaks into an electrical box. Water standing in the area around appliances or leaking into a conduit could also be a cause.
  • Worn or damaged wires can often be the cause of faults. Insulation around wires will wear down over time. Settling causes rocks or other objects to press against the sheath, damaging the cable/wires. Additionally, damage from rodents or bugs chewing the wires can be the result of underground faults 
  • Loose connections can result in a fault. For example, if a wire is not properly secured in a terminal. 
  • Miswiring can also result in the electrical charge taking another pathway to the ground.
  • Debris in an electrical box; this could even involve a build-up of dirt or dust!
  • A ground fault can occur when electrical appliances are damaged or have improper insulation.

How to Prevent Ground Faults

  • Now that we went over some situations that may cause ground faults, let’s talk about what measures need to be taken to prevent ground faults in the first place.
  • First, keep appliances, cables, and wires away from water and resolve any moisture issues before utilizing them! High-quality wiring is recommended to reduce the risk of poor insulation and malfunctions. Double-checking for damaged wires, debris removal, or loose connections can go a long way for your utmost safety. When installing wires or cables, put them in a conduit to protect them from damage. Also, ensure the presence of a ground wire so the straying currents can take a safe alternative path.
  • Ground fault circuit interrupters (GFCI’s) are used to prevent and keep you safe from ground faults. GFCI outlets and circuit breakers are effective in many ways. GFCI’s are used to monitor the amount of electric load passing through the circuit and interrupt the electric flow, especially when a ground fault is inspected. The electrical code requires GFCI’s in areas where moisture is present or water-prone areas. Ground faults can happen anytime and anywhere, but major damage can be caused in wet areas. Keep in mind that GFCIs do not last forever, either. If your GFCIs are getting old, consider investigating them closely and ensuring their accurate functioning so you can replace them at early signs of damage or risk. If you need help identifying a subsurface fault, contact professional assistance from undergroundfault detection experts.

Questions About Ground Fault Detection?

If you have any questions about our ground fault detection services (whether they are specific or general), please do not hesitate to contact us at (877)826-1177 or email [email protected]. We are happy to explain all of the services we offer in Oregon and Washington State.