In a residential service, the grounded conductor must not be smaller than which of the following?

The grounded conductor in a residential service must not be smaller than the grounding conductor to ensure safety and proper functionality within the electrical system. This requirement is based on the need to provide an effective path for fault currents and to maintain a safe and consistent ground potential.

The grounding conductor plays a vital role in preventing electrical shock and ensuring that any fault current can safely return to ground, minimizing the risk of fire or equipment damage. By ensuring that the grounded conductor is not smaller than the grounding conductor, the NEC aims to promote system integrity and reduce the risk of dangerous conditions.

While the other options reference various types of conductors that are part of the electrical system, none are directly related to the sizing requirements of the grounded conductor in a way that aligns with safety standards set forth by the NEC. The focus on the grounding conductor is crucial because it directly relates to the grounding and bonding requirements necessary for safe electrical installations.