For a grounded system, what type of main bonding jumper must be used?

In a grounded system, the main bonding jumper is crucial for ensuring that the neutral and grounding systems are effectively connected, allowing for safety and proper operation of electrical systems. The correct answer, which refers to an unspliced main bonding jumper, is essential because it provides a continuous and direct connection without any breaks or potential points of failure that could arise from splicing.

Using an unspliced main bonding jumper ensures that the physical integrity of the connection is maintained, allowing for optimal current flow and reducing the risk of resistance that might occur at splice points. This continuous connection is vital for ensuring that ground fault currents can be safely conducted back through the bonding system to ground.

In contrast, spliced jumpers would introduce potential issues such as increased resistance and the possibility of connection failure, while flexible or plastic jumpers may not meet the necessary conductivity or mechanical strength requirements essential for bonding in a grounded system. The materials and construction of the bonding jumper must also conform to relevant codes and standards to ensure safety and reliability.