Effective bonding of metal parts is required to maintain continuity to which point?

Effective bonding of metal parts is crucial for maintaining electrical continuity and safety throughout an electrical system. The principle behind effective bonding is to ensure that all metal parts are interconnected, thus providing a low-resistance path for fault currents and preventing the buildup of potential differences that can pose hazards.

When considering the options, bonding must be effective not only at the first panel board enclosure but also throughout the entire circuit, which includes the farthest outlet supplied and each receptacle in the branch circuit. This interconnectedness ensures that in the event of a fault, the electrical current can be effectively channeled back to the source, minimizing the risk of electric shock or fire.

By maintaining effective bonding at all these points, you ensure that all components, from the service entrance to the last outlet, are electrically continuous. This thorough bonding strategy provides a safety net that protects users and equipment alike, making it essential that all parts within the system, whether they are the first panel board or the last outlet, are effectively bonded. Thus, the correct answer encompasses all these critical points in the electrical system's bonding practice.