Which of the following describes an element that must be bonded in electrical systems?

The requirement for bonding applies specifically to grounding conductors within electrical systems. Grounding conductors serve a critical role by providing a safe path for electrical current to flow back to the ground in case of a fault, preventing electrical shock or fire hazards. Bonding involves connecting metal parts of the electrical system to ensure that all conductive components are at the same electrical potential. This helps to reduce the risk of electric shock by providing a safe route for potential fault currents and ensuring that the equipment operates safely.

Grounding conductors must be appropriately bonded to the grounding system to create a continuous conductive path. This bonding ensures that any electrical faults will result in protective devices, such as circuit breakers or fuses, activating to clear the fault, thereby enhancing safety and system integrity.

While insulated cables and mechanical connectors play important roles in electrical installations, they do not specifically require bonding in the same way that grounding conductors do. Feeder circuits are part of the electrical distribution system but are not elements that need to be bonded directly. Therefore, the requirement for bonding is inherently tied to grounding conductors, reflecting their essential role in maintaining safety in electrical systems.