If the source of a separately derived system is outside the building, where should the bonding jumper be installed?

The bonding jumper for a separately derived system should be installed at the grounding electrode connection to ensure safe and effective grounding of the electrical system. This location is essential because it helps to establish a low-resistance path between the separately derived system and the grounding electrode system, which is critical for managing fault currents and ensuring the system's safety.

Placing the bonding jumper at the grounding electrode connection allows for a direct and secure connection to the earth, which helps in stabilizing the voltage during fault conditions and providing protection against electrical shock. The proper bonding at this point is necessary for compliance with grounding and bonding requirements, ensuring that all parts of the electrical system are effectively connected to the ground.

Installing the bonding jumper at other locations, such as a main service panel, first load receptacle, or after the first disconnect, would not provide the same level of grounding effectiveness. These locations can introduce additional resistance or may not adequately connect to the grounding system, potentially compromising the safety and reliability of the electrical installation.