For an underground circuit to an isolated ground receptacle, what additional component should be pulled in along with the circuit conductors?

In an underground circuit to an isolated ground receptacle, both a neutral conductor and an equipment grounding conductor are necessary to ensure proper operation and safety. The neutral conductor is required to complete the circuit by providing a return path for current back to the source. This is essential for the functioning of the receptacle and connected equipment.

Meanwhile, the equipment grounding conductor serves a critical role in safety by providing a low-resistance path for fault currents. It ensures that any inadvertent fault, such as a short circuit or insulation failure, can safely direct the fault current to ground, which helps protect both the equipment and people from electrical shock hazards.

Using only a neutral conductor or only an equipment grounding conductor is insufficient, as this would not fulfill the requirements for both electrical continuity and safety. The isolated ground receptacle is designed for sensitive equipment that may be affected by noise or interference on the grounding system, so having both conductors ensures the integrity and safety of the installation.