Queensland is a large area with different types of soils and environments in four major regions: tropical, subtropical, coastal, and inland. Due to these variations in the nature of the earth, the question of how the electric current will flow into the ground is a big deal, and therefore earthing resistivity testing becomes a very important step in the creation of electrical systems that are both safe and compliant with regulations.
Firstly, for power infrastructure and substations, the situation is the same for renewable energy projects and commercial developments, where knowing the electrical behavior of the soil is a must. This article discusses how different types of soil in Queensland affect ERT testing, the importance of soil resistivity testing, and how the correct data helps in the proper design of the earthing system.
Earth resistivity testing is a method used to locate soil resistivity through the measure of the resistance that the ground opposes to the flow of an electric current. So, the results of the test are a guide to the engineers about the easy of the fault currents, lightning, or surge energy dissipation into the earth. Accurate ERT testing is essential for:
Without reliable soil resistivity data, earthing systems may underperform or require costly redesigns.
Queensland’s soil properties vary significantly due to differences in geology, rainfall, temperature, and mineral content. These factors directly affect electrical conductivity and, therefore, the effectiveness of earthing systems. Key influences on soil resistivity testing results include:
Because these conditions change from north to south Queensland, electrical resistivity testing must be site-specific rather than based on assumptions.
Northern Queensland is characterised by tropical climates, high rainfall, and often clay-rich soils. These conditions typically produce lower soil resistivity values, which are favourable for earthing systems. However, challenges can still arise:
ERT testing in northern Queensland often reveals strong contrasts between surface and deeper soil layers, highlighting the importance of multi-depth testing.
Central Queensland presents a mix of soil types, including sandy loams, red earths, and rocky substrates. Rainfall is less consistent, leading to greater seasonal changes in soil moisture. For earthing resistivity testing, this means:
Accurate soil resistivity testing in central Queensland helps engineers design earthing systems that remain effective throughout seasonal extremes.
Southern Queensland generally experiences cooler temperatures and lower rainfall, particularly in inland areas. These conditions often result in higher soil resistivity, which can pose challenges for effective earthing design. Common findings during ERT testing include:
In these regions, electrical resistivity testing is essential to identify deeper conductive layers or determine whether additional earthing measures are required.
Accurate ERT testing provides engineers with detailed insight into subsurface conditions, allowing for informed design decisions. Benefits include:
By understanding the true resistivity profile of the soil, designers can tailor earthing systems to local conditions rather than relying on generic assumptions.
To achieve reliable results across Queensland’s diverse soil environments, best practice earthing resistivity testing should include:
Professional ERT testing ensures data accuracy and supports safe, cost-effective electrical designs.
Variations in soil from the rain-fed areas of northern Queensland to the relatively dry southern parts have a major influence on how earthing systems work. Measuring the resistance of the soil is definitely not a standard procedure that can be the same for all cases — it has to take into account the different local conditions.
Through such a costly measure of the earth resistance test and the electrical resistivity test, the promoter or the engineer can be sure that the installation will be safe, the regulations will be complied with and the system will remain reliable for a long time out of the very different environments in Queensland.
For accurate soil resistivity testing and reliable geotechnical insights, get in touch with Tempsand Pty Ltd today, or call 0429-674-334 for more information.
