HV Earthing Design and Testing Services Australia
Protecting People and Equipment Through Compliant Earthing Systems
Earthing design is the engineering discipline of designing, modelling and testing an earthing system so a high-voltage installation can safely dissipate fault current into the ground while keeping step and touch voltages within safe limits. A correctly designed and tested earthing system is the primary means of protecting people from hazardous voltages during a high-voltage fault. Megavar delivers HV earthing design, earth grid design and earthing system testing for substations, renewable energy projects, BESS and industrial installations across Australia, to ENA EG-0, AS/NZS 4853 and IEEE 80.
A properly designed and tested earthing system is the primary means of protecting people from hazardous voltages during high-voltage faults. Inadequate earthing can result in dangerous step and touch potentials, equipment damage, and regulatory non-compliance. Megavar provides comprehensive HV earthing design and testing services for substations, renewable energy projects, industrial installations, and transmission infrastructure across Australia.
What is earthing design?
Earthing design is the process of sizing and arranging an earthing system so it safely carries the prospective fault current for its full duration. It starts with a soil resistivity survey, builds a layered soil model, then designs the earth grid geometry, conductor size and electrode arrangement, and verifies the result against permissible step and touch voltage limits.
What is soil resistivity testing?
Soil resistivity testing measures how readily the ground at a site conducts current, usually using the Wenner four-pin method at a range of electrode spacings. The results are modelled as a layered soil profile, which is the starting point for every earth grid design because soil resistivity directly determines the earth grid resistance that can be achieved.
What is earth resistance testing?
Earth resistance testing verifies that an installed earth grid achieves the resistance assumed in the design. The fall-of-potential method is the standard technique for measuring the resistance of a substation earth grid to remote earth, confirming the as-built system performs as designed before energisation.
Earthing Design Services
Soil Resistivity Surveys
Soil resistivity testing characterises the electrical resistivity of the ground at the project site using the Wenner four-pin method, taken along multiple traverses and at a range of electrode spacings. Megavar models the results as a layered soil profile, which sets the achievable earth grid resistance and underpins the entire earthing design. Soil resistivity surveys are carried out early so the earth grid can be sized correctly before construction.
Earth Grid Design
Megavar designs high-voltage earth grids from first principles for substations, renewable energy connections and industrial installations. Earth grid design covers conductor sizing for the prospective fault current and clearing time, grid geometry optimisation, buried conductor and electrode layout (driven rods, deep-driven electrodes and ground enhancement material where soil resistivity is high), and above-ground bonding of plant and structures. Every earth grid design is verified against the permissible step and touch voltage limits in ENA EG-0 and IEEE 80 before it is issued.
Substation Earthing
Substation earthing controls the earth potential rise during a fault and keeps step and touch voltages across the switchyard within safe limits. Megavar designs and tests substation earthing for transmission and distribution substations, including the main earth grid, fence and gate bonding, gradient control conductors, and surface layer treatment to raise the tolerable touch voltage. Design and as-built testing follow ENA EG-0, AS/NZS 4853 and IEEE 80.
Neutral Earthing Resistor (NER) Testing
A neutral earthing resistor limits the earth fault current in a generation or distribution system to a designed value, protecting plant and simplifying earth fault detection. Megavar tests NERs to verify the resistance value, continuity and connection integrity, and confirms the associated earth fault protection picks up and operates correctly. NER testing is carried out as part of substation commissioning and routine maintenance.
Step and Touch Potential Testing
Step and touch potential testing measures the actual voltages a person could be exposed to within and around an energised installation. Megavar measures step and touch potentials during staged fault injection and compares them against the permissible limits derived from ENA EG-0 and IEEE 80, validating the earthing design under real fault conditions and identifying any locations that need mitigation.
Earth Potential Rise (EPR) Analysis
Step and Touch Voltage Analysis
Transfer Potential Assessment
Earthing Testing Services
Earth resistance testing confirms that an installed earth grid achieves the resistance assumed in the design. Megavar uses the fall-of-potential method, and staged fault current injection where a large grid requires it, to measure the grid resistance to remote earth. The result is compared against the design value to confirm the as-built earthing system performs correctly before the installation is energised.
- Earth grid resistance — Fall-of-potential and staged fault testing methods to verify the earth grid resistance meets design requirements.
- Step and touch potential measurement — On-site measurement of actual step and touch voltages during staged fault injection to validate the design analysis.
- Soil resistivity measurement — Wenner four-pin surveys at multiple traverse directions and electrode spacings.
- Continuity testing — Verification of bonding connections, earthing conductor continuity, and equipotential zone integrity.
- Earth fault loop impedance — Measurement to verify fault current return path impedance for protection coordination.
Design Software
Megavar uses CDEGS (Current Distribution, Electromagnetic Fields, Grounding and Soil Structure Analysis) by SES Technologies — the industry-standard earthing design and analysis platform. CDEGS enables detailed 3D modelling of complex earth grid geometries and accurate prediction of surface potentials.
Check the AEMC 6471 ground resistance tester.
Frequently Asked Questions
HV (High-Voltage) Earthing Design and Testing Services
What is earth potential rise (EPR)?
EPR is the voltage that develops on an earthing system during a high-voltage fault. This voltage can be hazardous to people and can transfer onto metallic services (LV, telecoms, fences) that enter the EPR zone. Earthing design must ensure EPR is managed to within safe limits.
What standards apply to HV earthing in Australia?
What is a step and touch voltage study?
Does Megavar perform earthing testing during commissioning?
Can Megavar design earthing for difficult soil conditions?
Ready to commission your substation? Contact Megavar today on 1300 730 499 or visit our contact page to request a quote.
Why Choose Megavar for HV Earthing Design and Testing?
- Australia-Wide Expertise: Serving clients in all states and territories.
- Industry Compliance: Meeting AS/NZS and ENA standards.
- Custom Solutions: Tailored earthing designs for renewable energy, utilities, mining, and industrial applications.
- Minimised Risk & Optimised Performance: Reducing equipment failures and downtime.
- Ongoing Support: Providing maintenance, monitoring, and compliance updates.
Partner with Megavar for expert HV Earthing Design and Testing. Contact us today to discuss your project needs!
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