Earthing system design is PowerEarth’s founding specialisation. Since 1994, we have designed, tested and assessed earthing systems for some of Australia’s most critical electrical infrastructure, from high voltage substations and transmission networks to rail traction systems, mine sites and renewable energy installations.
Our engineers use CDEGS, the industry’s most powerful earthing and electromagnetic analysis software, to model earthing system behaviour under fault conditions and deliver designs that are safe, compliant and cost-effective. We design to Australian and international standards including AS 2067 (Substations and High Voltage Installations), ENA EG-0 (Power System Earthing Guide) and IEEE 80 (Guide for Safety in AC Substation Grounding), applying these across every sector we work in.
Our Earthing Design Capability
Earth Potential Rise (EPR) Studies
When a high voltage fault occurs, the flow of fault current through the earthing system causes the earth potential to rise. This EPR can be hazardous to people and can transfer dangerous voltages onto metallic services, including telecommunications, water pipes, gas pipelines and low voltage networks, that enter the EPR zone of influence. PowerEarth’s EPR studies use CDEGS modelling combined with site-specific soil resistivity data to calculate the magnitude and extent of EPR under fault conditions, identify hazardous voltage transfers to third-party assets and design mitigation measures that comply with AS 2067 and ENA EG-0 safety criteria.
Step, Touch and Transfer Voltage Assessments
Step voltage is the potential difference between a person’s feet during an earth fault. Touch voltage is the potential difference between a person’s hand (touching earthed equipment) and their feet. Transfer voltage occurs when hazardous potentials are carried to remote locations via metallic conductors. Our assessments calculate these voltages at every accessible location within and around the installation, compare them against the permissible limits derived from body impedance models in ENA EG-0 and AS 2067, and identify any locations requiring mitigation, such as surface treatment, insulating barriers, gradient control conductors or bonding modifications.
AC Interference and Low Frequency Induction (LFI)
High voltage power lines running parallel to metallic pipelines or telecommunications cables can induce hazardous voltages through electromagnetic coupling. PowerEarth evaluates AC interference risks for water and gas pipeline operators, telecommunications providers and other asset owners, calculating induced voltages under both steady-state and fault conditions and designing mitigation measures to reduce voltages to safe levels in accordance with AS/NZS 4853 (Electrical Hazards on Metallic Pipelines).
Electromagnetic Interference (EMI) Assessments
Sensitive electronic equipment, control systems and communications infrastructure can be affected by electromagnetic fields generated by high voltage and high current electrical installations. Our EMI assessments identify interference risks, quantify field exposure levels and design shielding or separation strategies to protect sensitive receivers, including signalling systems in rail corridors and instrumentation in industrial facilities.
Earthing and Bonding Management Plans
For AC and DC traction systems, PowerEarth develops comprehensive earthing and bonding management plans that address the unique challenges of rail electrification, including stray current control, return current management, touch voltage safety at platforms and crossings, and coordination between traction and utility earthing systems. These plans comply with relevant rail authority standards and are developed in close coordination with rail operators and infrastructure owners.
Electrolysis and Stray Current Assessment
DC traction systems and other DC power sources can produce stray currents that flow through the soil and corrode buried metallic infrastructure, including water mains, gas pipelines, cable sheaths and structural steel. PowerEarth’s electrolysis assessments model stray current paths, quantify corrosion risks and design mitigation systems including drainage bonds, insulating joints, cathodic protection coordination and monitoring instrumentation. We also provide AC corrosion monitoring and mitigation planning for pipelines affected by high voltage AC power lines.
Sector Applications
Earthing design and electrolysis challenges vary significantly across industries. PowerEarth’s experience spanning multiple sectors means we understand the specific standards, soil conditions and operational environments that influence each design:
- Power & utilities: Zone substation earthing design (11kV to 330kV), transmission line earthing, distribution substation earth grid design, EPR assessments for third-party asset protection
- Rail & transport: Traction return current earthing, stray current and electrolysis control, platform and crossing touch voltage management, earthing and bonding management plans
- Renewables & battery storage: Solar farm earth grid design, wind turbine earthing, BESS earthing systems, grid connection earthing studies
- Mining & industrial: Surface and underground earthing systems, high-resistivity soil solutions, process plant earthing design
- Defence: Secure facility earthing systems compliant with Defence-specific standards
- Water & gas: Pipeline AC interference and LFI assessments, cathodic protection coordination, pump station earthing
View our project portfolio to see examples of our earthing work across these sectors.
How We Deliver Earthing Design
PowerEarth follows a structured design process built on accurate site data, rigorous analysis and clear documentation:
- Site data collection: We conduct soil resistivity surveys using the Wenner four-pin method to characterise the electrical properties of the soil. Results are modelled in CDEGS RESAP to develop multi-layer soil resistivity models that form the foundation of all subsequent analysis.
- System modelling: Our engineers build detailed 3D CDEGS models of the earthing system, high voltage cables, overhead power lines and third-party infrastructure to accurately simulate fault conditions and current distribution.
- Hazard assessment: We calculate EPR, step voltages, touch voltages and transfer voltages for all worst-case fault scenarios, comparing results against the safety criteria in AS 2067 and ENA EG-0.
- Design optimisation: Where hazard voltages exceed permissible limits, we apply the hierarchy of controls to mitigate risks, including earth grid geometry optimisation, surface treatment, gradient control conductors, bonding modifications and isolation measures.
- Documentation and drawings: We deliver earthing general arrangement drawings, connection details, equipment schedules, a design basis report and compliance documentation in formats compatible with your project requirements.
Our earthing designs integrate with our electrical system design, lightning protection and testing and commissioning services, providing a complete solution from analysis to verification.
Frequently Asked Questions
What is an EPR study and when is it required?
An Earth Potential Rise (EPR) study calculates the voltage that develops on an earthing system during a high voltage fault. EPR studies are required for substations, switching stations and other high voltage installations where fault currents can create hazardous voltages on the earthing system and transfer them to nearby metallic infrastructure such as telecommunications, pipelines and low voltage networks. In Australia, EPR studies are required under AS 2067 and ENA EG-0 for all new high voltage installations and when existing installations are modified.
What Australian Standards apply to earthing system design?
The key standards include AS 2067 (Substations and High Voltage Installations) for HV earthing design, ENA EG-0 (Power System Earthing Guide) for risk-based earthing design methodology, AS/NZS 3000 (Wiring Rules) for LV installations, AS/NZS 4853 for electrical hazards on metallic pipelines, and IEEE 80 (Guide for Safety in AC Substation Grounding) which is widely referenced alongside Australian standards. Network operators may also impose additional requirements through their own earthing standards.
What is CDEGS and why does PowerEarth use it?
CDEGS (Current Distribution, Electromagnetic Fields, Grounding and Soil Structure Analysis) is the industry’s most powerful software package for earthing system modelling, electromagnetic interference analysis and transient simulations. PowerEarth uses CDEGS because it enables accurate 3D modelling of complex earthing systems, precise calculation of fault current distribution through overhead earth wires and cable screens, and reliable prediction of step and touch voltages under all fault scenarios. This accuracy is essential for delivering designs that are both safe and cost-effective.
What is electrolysis and why does it affect buried infrastructure?
Electrolysis in this context refers to the corrosion of buried metallic structures caused by stray direct current (DC) flowing through the soil. DC traction systems, such as those used in urban rail networks, are the most common source. The stray current leaves the rail, flows through the soil, enters buried metallic infrastructure (water mains, gas pipes, cable sheaths) and exits back to the traction substation, corroding the metal at the point of exit. PowerEarth’s electrolysis assessments model these current paths and design mitigation to protect affected assets.
Can you design earthing systems for high-resistivity soil?
Yes. High-resistivity soils (sandy, rocky or arid conditions) present significant earthing design challenges because they make it harder to achieve low earthing impedance. PowerEarth regularly designs earthing systems for these conditions using techniques including deep-driven electrodes, extended earth grids, ground enhancement materials, concrete-encased electrodes and interconnection of multiple earthing systems. Our CDEGS modelling accurately accounts for multi-layer soil resistivity profiles to optimise these designs.
What is the difference between step voltage and touch voltage?
Step voltage is the potential difference between a person’s feet (typically measured across a 1-metre stride) during an earth fault. Touch voltage is the potential difference between a person’s hand, for example, touching an earthed equipment enclosure, and their feet. Both must remain below permissible limits to ensure safety. The limits are calculated based on body impedance models and fault duration as specified in ENA EG-0 and AS 2067. PowerEarth calculates both during the design phase and verifies them through site testing during commissioning.
Talk to Our Earthing Team
Whether you need an EPR study for a new substation, an electrolysis assessment for a rail project, AC interference evaluation for a pipeline, or a complete earthing design for a greenfield site, PowerEarth’s engineers have the expertise, software and field experience to deliver. With 30 years as Australia’s earthing specialists, we provide designs that are safe, standards-compliant and optimised for your site conditions.
Contact us today to discuss your earthing requirements, or call us on 1300 POWEREARTH.