Safety assurance
Confirms the earthing system will carry fault current away safely.
Geotechnical Investigation
Earth Resistance Test (ERT)
Measurement of earth electrical resistance for earthing verification and subsurface characterisation.
Overview
Earth resistance testing measures how readily electrical current passes into the ground. It is used to verify earthing installations and to characterise subsurface conditions.
Earth resistance tests show how well an earthing system, or the ground itself, conducts electricity. A low, stable value keeps people and equipment safe during faults and lightning, and soil resistivity measurements guide how a new earthing system should be designed.
- Earthing installation verification
- Subsurface resistivity characterisation
- Field measurement with recorded results
Key Benefits
Design input
Soil resistivity data helps design efficient earthing.
Compliance evidence
Recorded values support acceptance and audits.
Detects deterioration
Periodic tests show corrosion or loose connections.
Where It Is Used
- Substations and power plants
- Telecom towers and data centres
- Industrial plants and buildings
- Lightning-protection systems
How We Work
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1
Review the layout
Identify electrodes, connections and test points.
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2
Set the test probes
Arrange current and potential probes at specified spacings.
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3
Measure
Record resistance or resistivity at each configuration.
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4
Assess and report
Compare against required limits and recommend improvements if needed.
What You Receive
- Measured resistance or resistivity values
- Test layout sketch
- Compliance comparison
- Test report
Frequently Asked Questions
What is a good earth resistance value?
It depends on the installation type and the applicable standard; the specified limit for your system is used as the pass criterion.
Does the season affect results?
Yes. Soil moisture changes resistance, so results are best interpreted with weather conditions in mind.
Have an infrastructure testing or monitoring requirement?
Tell us about your project — our engineering team will follow up on scope, instrumentation and approach.