What ensures fast trip-out operation of circuit protection devices in a grounding set?

The choice that ensures fast trip-out operation of circuit protection devices in a grounding set is based on the concept of bonding phases, the neutral, and earth together. This method reduces the impedance in the event of a fault, thereby allowing for quicker response times from circuit protection devices, such as circuit breakers or fuses.

When the phases, neutral, and earth are bonded effectively, any fault current has a clear and low-resistance path to ground. This minimizes the voltage level that can occur during a fault condition, allowing the protection devices to detect the fault more rapidly and react accordingly to isolate the faulted section of the circuit. This rapid response is crucial for maintaining system stability and protecting both personnel and equipment from potential damage.

Other methods like using a single phase connection or increasing the length of the conductor do not enhance the speed of trip-out operation. Single-phase connections can lead to unbalanced loading and do not optimize fault detection. Similarly, increasing conductor length typically increases impedance, which can actually hinder fault detection and response time. Utilizing resistors may serve specific functions in certain applications but does not directly contribute to improving the rapid trip response in grounding scenarios.