Function and Purpose of a Building Ground Riser

A building ground riser is a continuous electrical grounding path that extends from the electrical service entrance to the main grounding bus in a building. It serves the following functions:

Provides a Low-Resistance Grounding Path

The ground riser creates a low-impedance path for fault currents to flow back to the ground. This ensures that equipment and personnel are protected from electrical shock in the event of a fault.

Protects Against Lightning and Static Charges

The ground riser provides a safe path for lightning and static electricity to dissipate into the ground, minimizing the risk of damage to equipment and the building itself.

Ensures Proper Operation of Equipment

Grounding is essential for the proper operation of many electrical devices, such as surge suppressors, ground-fault circuit interrupters (GFCIs), and electronic equipment. A ground riser ensures that these devices have a stable and low-resistance ground connection.

Complies with Electrical Codes

Building ground risers are required by electrical codes, such as the National Electrical Code (NEC), to provide a safe and reliable grounding system.

Adequacy of Low Impedance EG on Every Feeder and Branch Circuit

While low impedance EG on every feeder and branch circuit is important for providing a path for fault currents, it does not replace the need for a building ground riser. The ground riser serves as a backup grounding path in case of multiple faults or if the EG fails. Additionally, the ground riser provides a common grounding point for all equipment in the building, ensuring that they are all at the same potential.

In summary, a building ground riser is an essential component of a complete grounding system that provides a low-resistance path for fault currents, protects against lightning and static charges, ensures proper equipment operation, and complies with electrical codes. Flag for review