In residential wiring, what must be included when using a subpanel?

When using a subpanel in residential wiring, it is essential to have separate grounding and bonding. This requirement ensures the safe operation of the electrical system by reducing the risk of electric shock and protecting against electrical faults.

In a subpanel, the ground and neutral conductors must be separated to prevent neutral current from flowing through the ground system, which can create a shock hazard and negate the protective function of the ground. The ground wire provides a path for fault current, while the neutral wire carries return current from the electrical load. Proper grounding and bonding help ensure that the electrical system functions safely and effectively, as well as meet the National Electrical Code (NEC) requirements mandated for subpanels.

Other choices may appear to be relevant in certain contexts, but they do not pertain to the fundamental requirement of grounding and bonding for subpanels, which is critical for safety and compliance with electrical codes.