What is the typical resistance value for grounding electrodes?

The typical resistance value for grounding electrodes is regarded as being below 25 ohms. This standard is established to ensure that the grounding system is effective in dissipating electrical energy safely into the ground. A lower resistance allows for a more efficient path for fault currents, minimizing the risk of electric shock or damage to equipment.

The National Electrical Code (NEC) and various electrical safety organizations recommend this value to ensure systems are adequately grounded, particularly in environments where electrical faults may occur. A resistance of under 25 ohms is usually sufficient to limit voltage rise during fault conditions, making it a common benchmark for grounding electrode performance.

In contrast, higher resistance values, like 50 ohms or 10 ohms, do not meet the safety and performance requirements typically needed for effective grounding systems. Therefore, grounding electrodes achieving a resistance below 25 ohms are favored to enhance safety and reliability in electrical installations.