What is the maximum permissible current difference for a GFCI to interrupt power?

The maximum permissible current difference for a Ground Fault Circuit Interrupter (GFCI) to interrupt power is indeed 6 mA. A GFCI is designed to detect ground faults by monitoring the current flowing through the circuit. When it detects a difference in current between the hot and neutral wires that exceeds the set threshold, it rapidly disconnects the circuit to prevent electric shock and potential electrocution.

The 6 mA threshold is established based on safety standards, as it is sufficient to protect against potentially dangerous ground faults while minimizing the risk of nuisance tripping. A current difference below this threshold may not pose a serious risk, while exceeding it can indicate a fault that could endanger individuals, especially in wet or damp locations where the risk of shock is heightened.

Setting a GFCI to interrupt the circuit at 6 mA balances efficacy in protecting users while maintaining reliable operation in a variety of conditions, as higher thresholds may not adequately protect against the safety risks associated with ground faults.