Following the installation of a new earthing system and periodically throughout the life of the earthing system, it should undergo earth testing to determine its electrical condition and ongoing level of performance. There are many factors that can cause degradation of an earthing system, with some of the contributory factors even occurring below the ground. Megavar engineers are earth testing experts and use state of the art testing equipment to perform the following earth system testing in accordance with IEEE81:
- Soil Resistivity
- Earthing System Impedance using Fall of Potential Method
- Voltage Contour measurements
- Step and Touch Potential
- Continuity Checks
Megavar engineers also perform inspections of the complete installation in accordance with AS2067-2008, AS3000 and ENA-EG1 2006.
A proper earthing design and earth testing regime is essential to ensuring the safety of personnel, plant and the public in the event of a power system fault. There are many conditions under which a power system fault can impress a voltage upon an earthing system with the two most common being through lightning strikes (causing flashover or diverted to earth through surge arrestors) and live conductors inadvertently contacting earth.
When this occurs, the resultant current gives rise to an increase in the earth potential in the immediate area around the fault. Having an earthing system that is adequately designed and properly maintained will offer protection to personnel, plant and the public by limiting the voltage rise and directing the current flow into the general mass of earth. An earthing system that directs current flow into the general mass of earth with little resistance or impedance also allows for correct operation of protection devices ensuring any faults are cleared in the minimum time possible offering maximum safety and ensuring power system stability.