Where are the system bonding jumper and grounding electrode conductor required to be installed when a transformer feeds a 120/208-volt, 3-phase, 4-wire main breaker panel?

The requirement for the installation of the system bonding jumper and grounding electrode conductor pertains to ensuring effective grounding and bonding in the electrical system to enhance safety and reduce the risk of electrical shock or fire.

In a typical scenario where a transformer feeds a main breaker panel, the system bonding jumper, which connects the grounded conductor to the grounding system, and the grounding electrode conductor, which connects the grounding system to the grounding electrodes, can be installed at either location—the transformer or the panel. The key point is that both components serve the purpose of establishing a continuous path for fault current back to the source, and they facilitate a safe and efficient grounding system.

Choosing to install these components at the transformer or the panel provides flexibility in the installation process, allowing electricians to choose the most practical method based on the specific installation conditions. This adaptability helps to accommodate various installation codes and local practices, ensuring that grounding is both effective and compliant.