The perfect resistance value for a copper bonded earthing rod really hinges on what you’re using it for and the local electrical codes. However, a common recommendation is to aim for a resistance-to-ground of less than 25 ohms for most standard electrical setups. This guideline comes straight from the National Electric Code (NEC) and serves as a solid benchmark for safe and effective ... https://www.pioneerpowers.com/copper-cable-lugs.php