Should each switchboard used as service equipment have a main bonding jumper?

The correct answer emphasizes the importance of safety in electrical installations. A main bonding jumper is essential in each switchboard used as service equipment because it creates a low-resistance path between the grounding electrode system and the neutral conductor. This connection is crucial in ensuring that in the event of a fault, such as a short circuit, the system can safely redirect fault currents to the ground, thereby preventing potential hazards like electric shock or fire.

The requirement for a main bonding jumper is a foundational aspect of maintaining system integrity and safety as outlined in recognized electrical standards, such as the National Electrical Code (NEC). This jump serves to stabilize the electrical system, helping to equalize voltage levels and minimize the risk of malfunction due to differences in potential.

Other options imply various misconceptions about when or why a main bonding jumper may be unnecessary, which would compromise safety standards established for electrical systems in different environments and voltages. All service equipment switchboards, regardless of their location or voltage level, require proper bonding to ensure safety and compliance with regulatory standards.