What are the common pitfalls of bonding multiple grounding systems in a facility?

1 Pitfall 1: Inadequate bonding conductors

One of the most common pitfalls of bonding multiple grounding systems in a facility is using inadequate bonding conductors that cannot handle the expected fault current or provide a low-impedance path to ground. Bonding conductors are the wires or cables that connect different grounding electrodes or systems together, such as the building steel, the water pipe, the generator frame, or the lightning protection system. If the bonding conductors are too small, too long, or poorly connected, they can create a voltage difference between the grounded parts, which can cause shock hazards, equipment damage, or electromagnetic interference. To avoid this pitfall, you should follow the recommendations of the National Electrical Code (NEC) or other relevant standards for sizing, routing, and terminating the bonding conductors.

2 Pitfall 2: Multiple ground rods

Another common pitfall of bonding multiple grounding systems in a facility is installing multiple ground rods without proper bonding. Ground rods are metal rods that are driven into the earth to provide a connection to the earth's potential. They are often used as grounding electrodes for electrical systems or equipment that need a separate ground reference, such as sensitive electronics, telecommunications, or lightning protection. However, if multiple ground rods are installed in different locations without being bonded together, they can create a loop or a parallel path for the fault current, which can reduce the effectiveness of the grounding system and increase the risk of ground faults or lightning strikes. To avoid this pitfall, you should bond all the ground rods together with a suitable bonding conductor and connect them to the main grounding electrode or system of the facility.

3 Pitfall 3: Improper isolation

A third common pitfall of bonding multiple grounding systems in a facility is failing to isolate the systems that need to be isolated from each other. Some electrical systems or equipment may require isolation from the main grounding system of the facility for functional or safety reasons, such as isolated power systems in health care facilities, uninterruptible power supplies (UPS) for critical loads, or surge protective devices (SPD) for transient protection. If these systems are not properly isolated from the main grounding system, they can cause unwanted interactions, such as noise, harmonics, or overvoltage, that can affect the performance or reliability of the systems or equipment. To avoid this pitfall, you should follow the manufacturer's instructions and the applicable codes and standards for isolating the systems that need to be isolated and ensuring that they have their own grounding electrodes or systems.

4 Pitfall 4: Inconsistent labeling

A fourth common pitfall of bonding multiple grounding systems in a facility is neglecting to label the systems and their components clearly and consistently. Labeling is important for identifying the purpose, function, and location of the different grounding systems and their components, such as the grounding electrodes, the bonding conductors, the grounding buses, or the grounding terminals. Labeling can also help prevent confusion, errors, or accidents during installation, maintenance, testing, or troubleshooting of the grounding systems. To avoid this pitfall, you should use durable and visible labels that follow the conventions and requirements of the NEC or other relevant standards for marking the grounding systems and their components.

5 Pitfall 5: Lack of coordination

A fifth common pitfall of bonding multiple grounding systems in a facility is failing to coordinate the design, installation, and verification of the systems with all the stakeholders involved. Bonding multiple grounding systems in a facility is not a one-person or one-discipline job. It requires the collaboration and communication of various parties, such as the owner, the engineer, the contractor, the electrician, the inspector, and the equipment manufacturer. If there is a lack of coordination among these parties, it can result in conflicts, inconsistencies, or errors that can compromise the quality and safety of the grounding systems. To avoid this pitfall, you should establish a clear and comprehensive plan for bonding multiple grounding systems in a facility and involve all the stakeholders in every stage of the process.

6 Pitfall 6: Insufficient testing

A sixth common pitfall of bonding multiple grounding systems in a facility is skipping or skimping on testing the systems after installation or modification. Testing is essential for verifying that the grounding systems are functioning properly and meeting the specifications and expectations. Testing can also help identify and correct any defects, issues, or deviations that may have occurred during installation or modification. Some of the common tests that should be performed on the grounding systems include resistance, continuity, impedance, and bonding measurements. To avoid this pitfall, you should follow the best practices and guidelines of the IEEE or other relevant standards for testing the grounding systems and documenting the results.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?