If ungrounded service-entrance conductors are installed in parallel, what must also be done with the grounded conductor?

When ungrounded service-entrance conductors are installed in parallel, the grounded conductor must also be installed in parallel to ensure proper balance and performance of the electrical system. This is essential for maintaining an effective grounding system, as the grounded conductor serves as a return path for current.

Installing both the ungrounded and grounded conductors in parallel helps to ensure that voltage drops remain consistent across the conductors and that any potential fault conditions are effectively managed. If the grounded conductor were not installed in parallel, it could result in an imbalance in the system, leading to unsafe conditions or inadequate performance.

Moreover, having the grounded conductor in parallel allows for effective bonding in the system, reducing the risk of shock hazards, and helps to facilitate proper operation of overcurrent protective devices. This is particularly important in maintaining the safety standards required in electrical installations.