Earth Resistance Reduction with Bentonite/Ground Enhancement Material
Application of a conductive ground enhancement material (such as bentonite clay or a purpose-designed conductive concrete/gel, tested to IEC 62561-7) around an earth electrode in soils with high resistivity (for example rocky or very dry ground), to achieve the required earth resistance without having to install a disproportionate number or length of electrodes. The material is hygroscopic and retains moisture around the electrode, effectively increasing the contact area with the surrounding soil and lowering the contact resistance. Unlike a one-off salt treatment of the soil, a well-chosen ground enhancement material is chemically stable and non-corrosive to the electrode, and its effect persists over the service life of the earthing installation rather than leaching out after a few years.
Bij een bliksembeveiligingsinstallatie op een rotsachtig bouwterrein past de installateur bentoniet rondom de staafaarders toe om de vereiste aardweerstand van de LPS te behalen zonder een onpraktisch uitgebreid aardnet te moeten aanleggen.
Gewoon keukenzout in de grond rondom een aardelektrode strooien om de weerstand snel te verlagen — dit werkt tijdelijk maar spoelt binnen enkele seizoenen uit én versnelt de corrosie van de elektrode zelf, in tegenstelling tot een gecertificeerde, niet-corrosieve grondverbeteraar.
See also
- → §542 (elektrodemateriaal) Galvanic corrosion of earth electrodes — material choice copper versus steel
- → §542 Earth Electrodes — Foundation Earth Electrode, Rod and Ring Electrodes (§542)
- → §542 / IEC 60364-5-54 Sizing an earth electrode — the calculation formulas for rod and plate electrodes
- → IEEE 80 / praktijk Ground enhancement material (bentonite, conductive concrete) in high-resistivity soil — when extra earth electrodes are not enough
- → §444.6 / IEC 60364-4-44 Functional earthing (FE) versus protective earthing (PE) — two different purposes, with or without a shared conductor
- → IEC 60364-7-712 / NEC 690.12 PV rapid shutdown — quickly lowering rooftop voltage for the fire service