By Steve Wood, Senior Trainer and Assessor, CERTLOC

Accurate and reliable locating depends on the strength and quality of the signal transmitted and received along a target asset. In this edition, we examine how the distance of the earth stake from the target asset, the use of earth mats, and the ground conditions affects the resultant current and signal strength. The results are based on testing conducted with a 600mm mild steel water main connected via an electrolysis test point, with the transmitter frequency set at 8 kHz and a signal strength of 10%, while the receiver gain was standardised at 93dB.

Test Scenarios and Results

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Scenario 1: Earth Stake at Full Extent of Direct Connect Leads

• Transmitter (Tx): 5mA and 1.3 volts
• Receiver (Rx): 0.93mA and 74.9% signal strength

Placing the earth stake at the full extent of the direct connect leads resulted in strong current flow and excellent signal strength at the receiver.

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Scenario 2: Earth Stake 1 Metre from Target Pipe

• Transmitter (Tx): 5mA and 0.9 volts
• Receiver (Rx): 0.39mA and 34.1% signal strength

The earth stake being close to the target asset resulted in reduced current and weaker signal strength resulting also in reduced trace length.

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Scenario 3: Single Earth Mat at Full Extent of Direct Connect Leads

• Transmitter (Tx): 2mA and 29.9 volts
• Receiver (Rx): 0.42mA and 35.6% signal strength

Using a single earth mat provides a signal strength but not as good as the earth stake.

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Scenario 4: Two Earth Mats at Full Extent of Direct Connect Leads

• Transmitter (Tx): 4mA and 29.9 volts
• Receiver (Rx): 0.78mA and 62.8% signal strength

Doubling the earth mats significantly enhanced the surface area of the ground connection. This led to a considerable improvement in both the current and the signal strength. But still not as good as the earth stake.

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Scenario 5: One Earth Mat on Gravel

• Transmitter (Tx): 0mA and 29.9 volts
• Receiver (Rx): No signal detected

Gravel acted as an insulator, preventing effective current flow, and no signal was detected.

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Scenario 6: Two Earth Mats on Gravel

• Transmitter (Tx): 0mA and 29.9 volts
• Receiver (Rx): No signal detected

Doubling the earth mats did not overcome the poor conductivity of gravel, reaffirming its limitations as a grounding medium.

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Scenario 7: Two Earth Mats on Concrete

• Transmitter (Tx): 1mA and 30 volts
• Receiver (Rx): 0.27mA and 23.2% signal strength

Concrete, while slightly conductive, limited the current flow and resulted in a weak signal.

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Scenario 8: Two Earth Mats on Concrete with Water Added

• Transmitter (Tx): 5mA and 2.6 volts
• Receiver (Rx): 0.99mA and 80.5% signal strength

Adding water to the concrete dramatically improved conductivity, resulting in the highest signal strength observed during testing.

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Key Conclusions

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This study underscores the importance of understanding and optimising ground connections in locating operations. These findings help Certified Locators achieve stronger, more reliable signals, even in challenging conditions, ensuring the accurate identification and mapping of underground assets.

For more insights and technical updates, be sure to look out for the next edition of Technical Tips for Certified Locators.

As leading Australian safety and utility damage prevention advocates, the renowned global leader formerly known as DBYD Certification Ltd (DCL) has rebranded to CERTLOC. As a Certified Locator Institute, CERTLOC is making a significant leap towards improving underground location services and qualification standards in Australia.

CERTLOC led by Robert Row, has been a CEO of construction industry associations and training organisations for over 30 years, in addition to previous roles like National Chair and State President for Group Training Australia, Member of Infrastructure Queensland reporting to the Deputy Premier of Queensland, and Director of Construction Skills Queensland, CERTLOC is set to revolutionise how the locator industry educates and certifies Locating Organisations and Locators.

The transition to CERTLOC is more than a rebranding; it’s a commitment to fundamentally changing how we approach locator certification and underground asset safety. Our aim is to address the specific challenges faced by the industry, providing solutions that not only tackle immediate problems but also pave the way for long-term improvement.

At CERTLOC, we are dedicated to saving lives, preventing utility damage, and ensuring the protection of people, communities, and asset owners worldwide. Our vision is to lead the industry towards higher safety and qualification standards by offering certifications that demand the adoption of best practices and the application of the latest, world-leading information and education.

We believe that the path to achieving unparalleled safety and expertise in underground asset location and management lies in collaboration. Utilities, civil construction firms, councils, and government organisations are invited to join this movement. Together, we can lead the charge in enhancing locator, community, site and underground asset safety across Australia and the globe.

Don’t settle for skilled, demand CERTLOC^TM Certified.

For partnership inquiries and further information on how to get involved with CERTLOC, please contact us.

 

About CERTLOC

CERTLOC, formerly known as DBYD Certification, is a global leader in safety advocacy, dedicated to transforming the underground asset industry by providing world-class locator certifications. With a focus on safety, expertise, and community protection, CERTLOC represents the future of underground asset location and safety standards.

 

About Robert Row

Robert has made significant contributions to the construction sector, particularly in utility damage prevention, through various leadership roles including as CEO of DBYD Certification Ltd. His international speaking engagements have highlighted the importance of safer, more efficient construction and damage prevention practices globally. With an MBA and affiliations with prestigious Australian institutes, Robert’s career is marked by a dedication to enhancing industry standards, promoting safety, and developing skills within the construction and training industry.

By Steve Wood, Senior Trainer and Assessor, CERTLOC

In our previous article, “The Signal: Edition 2,” we explored the creation of the signal by applying a voltage to the target and enabling the voltage to travel back to the transmitter, establishing current flow and generating the electromagnetic field we detect. However, an important question arises: “How does the voltage leave an insulated copper cable or a coated gas or water main?” 

Far End Earthing 

The optimal method is through Far End Earthing, where the end of the target is connected to the earth/ground. Here, the voltage and current travel to the end of the target, then into the ground, and back to the source. This method ensures a stronger and more consistent signal along the target line. Unfortunately, most targets are not far end earthed. One interesting exception is electrical cables due to the Multiple Earthed Neutral (M.E.N.) system, which we will address in another edition. 

Capacitance 

More commonly, current and voltage flow due to Capacitance. A capacitor charges up with electricity and discharges rapidly. When something conductive is insulated and buried in the ground, it becomes a capacitor. Thus, the voltage and current discharge into the ground as they travel along the target. The efficiency of this process depends on two key factors: the length buried in the ground and the amount of conductive material inside the target. 

For instance, a 400-pair Telstra copper cable provides a better signal than a 10-pair cable. If you’ve ever placed an induction clamp around a 2-pair lead into a house from a pit, you likely experienced no signal at all or possibly a very weak signal due to the minimal copper content and the lack of earthing at the house. To overcome this, move the clamp further away or, ideally, use Direct Connect to the target. 

Practical Considerations 

• Induction Clamp and Capacitance: The signal travels equally in both directions from the clamp. If you experience no or poor signal, the target is likely cut or ends close to the clamp’s position. 

• Direct Connect: This method ensures the signal travels from one end outward, making it the preferred connection method. 

• Alternating Current (AC) vs. Direct Current (DC): We use AC because it can pass through a capacitor, while DC cannot. 

• Signal Dissipation: The signal dissipates proportionally to the target’s length. Thus, the longer the target, the slower the signal reduction. 

• Traceable Rods: These rely on capacitance, so insert as much rod as possible to improve the signal. Consider Far End Earthing the rod if it can reach another pit, significantly enhancing the signal. 

• Frequency Adjustment: Increasing the frequency can help but be cautious of potential issues like signal distortion or mutual induction, leading to ghosting on nearby conductive assets. 

Conclusion 

Understanding the roles of capacitance and far end earthing is vital for Certified Locators to achieve accurate and reliable results. Each method has its nuances, and applying the right techniques can significantly improve signal detection and asset location accuracy. 

For more insights and technical updates, be sure to look out for the next edition of Technical Tips for Certified Locators. Your feedback, questions, and input are always welcome. 

The article explains the fundamentals of locating buried assets using Electro Magnetic Fields (EMF). It covers signal generation, current flow, and the impact of ground conditions, emphasising the importance of understanding these principles for accurate asset location.

By Steve Wood, Senior Trainer and Assessor, CERTLOC

Introduction to Locating Buried Assets

In the world of Certified Locators, the term “signal” is fundamental. But what exactly is this signal? How is it generated, and what factors influence its behaviour? Understanding these intricacies is crucial for reliable asset location, ensuring we create a reliable signal that we can trace, place our marks accurately and avoid misidentifications.

The Nature of the Signal

At its core, the signal we use to locate buried assets is an Electro Magnetic Field (EMF). You may have heard terms like EMF locator, EMF locating, or reliable EMF locate. Sometimes, it’s referred to as Electro Magnetic Induction (EMI). Although the concept dates back to the early 1900s, advancements in technology have enhanced our ability to apply, detect, and interpret these signals effectively.

Creating the Electro Magnetic Field

The EMF signal is generated by current, specifically Alternating Current (AC) for two reasons: inductance and capacitance. Any conductive object carrying current will have an EMF around it. However, for current to flow, we need two key components: voltage and a circuit.

Your EMF locator consists of a receiver and a transmitter, with the transmitter being responsible for generating the voltage. This voltage can be emitted at various frequencies, which we will discuss later. The goal is to create a current flow, where the voltage leaves the transmitter through direct connect, induction clamp, or spill induction—all of which operate differently and have unique challenges.

Establishing the Current Flow

The voltage applied to the target asset travels along the asset, into the ground, and back to the source, creating a current flow and consequently an EMF that we can detect. Unlike typical electrical circuits, where current travels through conductive material like copper wires, our current must traverse the ground. This introduces complexities like Far End Earthing and Capacitance, which we’ll explore further.

Challenges and Ground Conditions

Ground conditions significantly impact the amount of current and the resultant signal. No two locates will ever be identical due to these variables. Understanding these factors helps explain why signals might be weak, poor, or distorted—each presenting unique challenges. Additionally, an overly strong signal can create other issues that need addressing.

Becoming a Certified Locator

Becoming a Certified Locator requires a deep understanding of these principles. Over the coming weeks, I’ll delve into these topics in greater detail and invite your feedback, questions, and input.

Stay tuned for more technical tips and insights!

By Steve Wood, Senior Trainer and Assessor, CERTLOC

Understanding the intricacies of locating high voltage (HV) electrical systems in passive mode is crucial for Certified Locators. Let’s delve into the essential aspects and best practices for accurately identifying these critical infrastructures.

The Basics of Power Passive Mode

First, it’s important to remember that the passive noise detected in Power Passive mode is created by the nine harmonics resulting from current flowing through the cable. The signal strength is influenced by the amount of current. If a cable is dead (no voltage or current) or alive (voltage but no current), it won’t produce the harmonic noise we detect. If passive signal detected in either of these situations it is due to harmonic noise from another source.

Distinguishing HV from LV

In the image, we see both High Voltage (HV) and Low Voltage (LV) cables.

Which one is which:

• Insulators: HV cables have larger insulators than LV cables.
• Aerial cable to house. This will be LV.
• Conductors: LV cables typically have four conductors—three actives and one neutral, with current flowing out on the active conductors and returning on the neutral conductor. HV cables have three active conductors but no neutral, with the return path being through the ground via a Power System Return Current Earth Grid.

The Power System Return Current Earth Grid is potentially very dangerous and distinct from fault protection earths, a topic for another day.

Balancing the Load

To minimise current on the Return Current Earth Grid, power distribution companies strive to balance the load across the phases. When the current is equal on each phase, the harmonic noise is neutralised, and no Power Passive signal is detected. An unbalanced load results in a Power Passive signal proportional to the imbalanced load (current).

Voltage increases as you approach the generation source and the load balance improves, too. The higher the voltage, the less likely it is to be detected using Power Passive mode.

This is specific to multi-phase transformers, such as two-wire or three-wire systems. Single Wire Earth Return (SWER) systems are different and potentially more hazardous, meriting another article.

Differences in Locating Practices

Locating practices vary between regions. In North America, for example, electrical grids often involve centre-tapping of transformer windings, leading to inevitable out-of-balance currents. Therefore, far more likely to be detected in Power Passive mode.

Key Takeaways

Always remember the following:

1. Power Passive signal does NOT identify HV or even LV power cables: It only identifies something metallic or conductive in the ground.
2. Verify HV location: If someone else locates the HV for you and says it’s not in the work area, ask them to specify its exact location.
3. Exercise extreme caution: High Voltage is one of the most dangerous assets in the ground and is challenging to locate. Always approach any electrical cables with the utmost caution.

Understanding these principles helps ensure the safety of workers and the community, reducing the risk of accidental strikes on critical infrastructure. Stay informed, stay cautious, and continue promoting industry best practices for a safer working environment.

In a tale of resilience and determination, Jessie McCracken is currently one of only nine women in Australia who are Certified Locators. Transitioning from corporate accounting to construction sites, her journey exemplifies the expanding horizons for women in traditionally male-dominated fields.

As an accountant, she was well accustomed to corporate life, but following the birth of her daughter and the unexpected separation from her husband just four days later, Jessie found herself in a challenging personal situation.

Jessie needed a career change, one that offered flexibility to manage the demands of single motherhood. Through assisting her parent’s earthmoving company, which utilised vacuum excavation trucks, she discovered the world of utility locating. Witnessing the work first-hand, Jessie saw an opportunity that fit her needs.

Jessie contacted a local Certified Locator that she knew of through her parents, Paul from CUSL (Cairns Underground Service Locators).

With Paul nearing retirement, Jessie enquired about the possibility of shadowing him to learn the ropes of locating. This initial request turned into Paul training and mentoring Jessie for a year, allowing her to gain valuable experience before pursuing formal certification through DBYD Certification with a goal to take over Paul’s business. She took over the service area and some of the clientele but had the freedom to take the business and make it her own.

Balancing motherhood and a demanding new skillset presented unique challenges. This period meant that she was breastfeeding between locating jobs, all while learning a new career.

In 2021, she took a bold step and founded Northern Underground Cable Finder, and ensured they became a Certified Locating Organisation. Through her company, she actively promotes a more inclusive and diverse workforce in the industry.

Trading high heels for steel-capped boots, Jessie’s story is an inspiration. Showcasing the exciting and flexible opportunities in utility locating for women, mothers, and younger generations. But her work goes beyond navigating underground networks. Safety is her focus. By ensuring the accurate identification of buried utilities, Jessie protects workers, infrastructure, and the communities she serves.

As she breaks barriers and explores new territories, Jessie McCracken’s journey reminds us that with determination and perseverance, any obstacle can be overcome, and any dream can be realised.

If you’re interested in connecting with Jessie or Northern Underground Cable Finder, feel free to reach out.

Northern Underground Cable Finder

Becoming a Certified Locator is a significant milestone in the career of every underground utility professional. We had the pleasure of sitting down with Earnest Banhwa, the Principal Surveyor at Precise Positioning Solutions Pty Ltd, to delve into his experience with the Certified Locator journey. 

Name: Earnest Banhwa
Position: Principal Surveyor
Organisation: Precise Positioning Solutions Pty Ltd
State: Queensland
Locator Experience: 3 years

Q: What does becoming a Certified Locator mean to you?

Becoming a Certified Locator is more than just a title; it’s a testament to our company’s ability to deliver both surveying and cable locating services. It adds a layer of credibility that resonates with potential clients, emphasising our commitment to excellence in the field. 

Q: What was the most challenging aspect of the process?

The journey to certification was not without its hurdles. I began my training amidst the peak of the Covid-19 pandemic, which led to logistical challenges. Traveling from Rockhampton to Brisbane for face-to-face training and later the practical assessment was a task in itself. Several postponements prolonged the certification process, testing both my patience and dedication. 

Q: What is your favourite thing about being a Certified Locator?

Being involved in the initial phases for construction projects is exciting. Construction should not commence without knowing what lies beneath the surface. As a locator and surveyor, I play a critical role in ensuring a safe and informed beginning to these projects. 

Q: Share a dangerous/interesting/funny/strange situation during a locate.

Locating in thick and tall grass and  encountering snakes is keeping me on high alert in those situations. Opening broken pits can also present unforeseen dangers. With my surveying background, the ability to now open pits and trace from one pit to another pit added an interesting dimension to my work. 

Q: When doing locating work, what does safety mean to you?

Safety is paramount. Before starting any locating activity, I do a comprehensive safety assessment. I want to return to my family in the same state I left home in the morning.  

Q: What tip would you give to other locators interested in becoming certified?

Enrol in a formal training course and, most importantly, never stop practising. Continuous learning and hands-on experience are key to mastering the required skills. 

By sharing his insights, Earnest invites fellow locators to embrace the Certified Locator journey. His experiences, from facing challenges to relishing the fascinating aspects of the job, reflect the dedication required in this crucial role. Safety, professionalism, and continuous learning define the path to becoming a Certified Locator. 

If you’re interested in connecting with Earnest or Precise Positioning Services, feel free to reach out:

LinkedIn – Earnest Banhwa
LinkedIn – Precise Positioning Solutions Pty Ltd  

Ben Whitfield, Service Locator at Locate Scan and Survey in NSW, has recently achieved a significant milestone in his career by becoming a Certified Locator.

With over three years locating experience in Sydney and the UK, Ben brings a variety of expertise to his role in underground service location. For Ben, obtaining certification is a testament to his hard work and dedication.

“It means a lot to me,” Ben explains. “Hard work pays off, and now getting recognised for it through the certification opens a lot more doors for me.” 

Highlighting city centres as one of the most daunting aspects of locating work, Ben mentions the complexity of numerous services, public traffic, and bustling environments as factors to these challenging locating sites. Because of these challenges, successfully completing projects in these types of areas, gives a sense of accomplishment and a recognition of learned skills.  

 One part Ben enjoys most about being a Certified Locator is the thrill of the unknown.

“With not being able to physically see the services, it’s almost like ‘The Unknown,” Ben shares. “Being able to successfully map out all aspects of underground services gives great satisfaction.”

 Throughout his career, Ben has encountered some interesting locations, from the various regions in New South Wales to the capital, Canberra, each place holds its own unique charm and challenges, contributing to Ben’s professional growth. 

When it comes to safety in locating work, Ben stresses its importance. “Safety is crucial on any working site. You are responsible for the safety of others and yourself when locating underground services,” Ben affirms, underlining that it extends beyond equipment usage to fostering a secure environment for all individuals participating in the process. 

For aspiring locators interested in becoming certified, Ben offers valuable advice:

“Take your time to learn the trade and all the stages that go with it. It’s not a job where you can cut corners. Don’t be afraid to ask questions.” 

 We congratulate Ben on his achievement and wish him continued success as a Certified Locator.  

 

If you’re interested in connecting with Ben or Locate Scan & Survey, feel free to reach out:

Connect with Locate Scan & Survey 

Find out more about becoming a Certified Locator here.  

To contact a Certified Locator for your next project search here.  

Meet Riley Brown, a newly Certified Locator from the Wollongong area of NSW. With 18 months of hands-on experience with A1 Locate Services Pty Ltd Riley offers insights into the significance of achieving certification and his passion for the role of underground services locator. 

For Riley, becoming certified as a locator is a big achievement and boosts his confidence in the industry. 

It is more than just career progression for him. It represents a personal milestone, having proven his skills and competency.  

The path to certification for Riley wasn’t without its hurdles.  Riley openly shares that the theoretical aspects of the certification process posed a unique challenge due to his Dyslexia. However, his determination to succeed and the support around him helped him to achieve his goal.  

Riley’s favourite aspect of the job is the difference that each site presents: “Every location or site is different, which is part of the challenge. Locating and marking utilities to expose what was previously just a blank canvas with potential hidden dangers is an exciting process. Finding those underground services that the client wasn’t aware of and minimising the risk of damage to utilities is one of my favourite parts of being a locator.” 

A self-confessed outdoors guy, some of his most memorable work locations would have to be the National Parks in NSW. The dense bushland and rugged terrain make locating extra interesting in these areas, with the native flora and fauna adding an additional layer of complexity to his locating work. 

Safety is paramount when working around utilities. Ensuring a secure and safer worksite environment is fundamental and in Riley’s world, it’s a crucial aspect of the locating process, especially on complex worksites. 

For those looking to get certified, he offers a simple yet invaluable piece of advice “do not rush the process.” He emphasises the significance of gaining practical experience prior to attempting the assessment.  

If you’re interested in connecting with Riley or A1 Locate Services Pty Ltd, feel free to reach out: 

Connect with A1 Locate Services Pty Ltd 

Find out more about becoming a Certified Locator here.  

To contact a Certified Locator for your next project search here.  

“Getting certified was a validation of my learning, skills and also a key step in my career progression. It signifies my dedication to upholding the industry’s stringent standards and DBYD Certification’s rigorous assessments,” Charlie affirmed. 

 Reflecting on the certification process, Charlie acknowledged facing two significant challenges. Overcoming test anxiety was crucial, necessitating practice until procedures became second nature. Slowing down during the practical assessment and approaching it methodically boosted confidence, allowing a comprehensive display of acquired skills and knowledge. 

“Learning to distinguish Telstra cables posed a notable hurdle. Once I referred to a Telstra cable guide online, decoding acronyms that I was confused by, it became clear, resolving any ongoing issues,” Charlie recounted.

Expressing passion for the role, Charlie highlighted the appeal of service locating was that it matches his curious nature. He shared how eager he is in learning how things work – from how the locating equipment works through to how the various utility systems work. 

Having the confidence in advising a client on where the underground services are located, by marking them correctly, is a critical component to mitigate risk before ground-disturbing.

Charlie recounts an incident at a new estate that exposed one client’s disregard for marked services: “I had a job locating all the services in the nature strips of a new estate so they could maintain a safe 1.5 m from services when planting trees. When I arrived on day 2 of the job, the mini excavator was already at work digging holes for the trees, directly over the power and gas lines I had already marked, occasionally ripping up the marker take for the LV. After speaking with the site manager, it became apparent that they were planting trees according to ‘the plan’ regardless of the actual position of services. I had marked the service clearly, provided relevant information on clearances required for services and made sure I kept notes on all of it. It was a lesson for me that as a locator I can do the locations and provide information, but ultimately, it is up to the client to use that information and determine the next steps. This was a great reminder to take photos and notes and to get the job sheet signed off to CYA.”

For those aspiring to enter the field of service locating, Charlie offers practical advice. “Get comfortable reading complex Telstra plans, practice the locate process until it becomes habit, and look for opportunities to locate less-common services,” he suggests.

“I would go for a walk to grab a coffee and I would look for all the pits, valves and connection points. Then I would go over in my head the method of connection I would use, doing a 360 sweep, how I would trouble shoot a poor signal.” Creating these repeatable processes allowed Charlie to become the confident Certified Locator he is today. 

Proactive learning, a curiosity for problem solving and a solid process will help you on your path to becoming Certified.  

If you’re interested in connecting with Charlie or DWB Engineering, feel free to reach out:

Connect with DWB Engineering on LinkedIn.  

Find out more about becoming a Certified Locator here. 

To contact a Certified Locator for your next project search here.