Can Aluminum Wiring Be Used for House Grounding Purposes?

When it comes to grounding in residential electrical systems, aluminum wiring can indeed be used, but with certain limitations and considerations. This article explores the usage of aluminum grounding wires, the advantages and disadvantages, and best practices for ensuring optimal safety and functionality.

Understanding Aluminum Wiring and Its Usage

Aluminum wiring is widely used in many residential electrical systems, particularly in the United States. However, its use in grounding purposes may be subject to specific regulations and practices to ensure safety.

Aluminum cables can be used to run a 2 Grounding Electrode Conductor to the metallic water service within 5 feet of where it enters the house, as seen in a 200 amp service installation. This is permissible in certain circumstances but must comply with specific guidelines.

Limitations of Aluminum Wire in Grounding

One key limitation of using aluminum wire for grounding is its inherent properties. According to electrical codes and standards, aluminum wire cannot be used within 18” of the earth. This means it cannot be used for a ground rod. Instead, it is typically used as a Grounding Electrode Conductor to a metallic water service pipe within 5 feet of where it enters the house.

Considerations for using aluminum wire for grounding include the fact that the ground wire may need to handle fault currents of hundreds of amperes. Thus, it must have a low resistance to avoid voltage drops that could cause safety hazards such as fires or electrocution. The ground wire's resistance is critical, especially if it is to take a significant current load.

Material Selection for Grounding Wires

The grounding conductor is usually made of copper due to its low resistance and durability. However, aluminum or copper-clad aluminum wire can be used as long as it does not come into contact with masonry or the earth. It is essential to ensure that the wire is not within 18 inches of the earth to avoid corrosion and safety issues.

Why Choose Copper for Better Performance

According to Dave, a professional in the telecommunications industry, copper wire generally outperforms aluminum wire in grounding applications. Here are some reasons why:

Higher Performance: Copper has better conductivity than aluminum, making it more reliable under varied conditions. Standard Practice: Copper is the preferred material in training documentation and standard industry practice. Thicker Gauge: To provide the same level of protection, aluminum would need to be a thicker gauge, which could affect the overall system's performance and costs.

Additionally, the corrosive properties of aluminum can be problematic over time. The ground spike typically used is made of copper or copper-coated steel, which should not be mixed with aluminum to prevent galvanic corrosion in damp environments.

Conclusion and Best Practices

While aluminum wiring can be used for grounding in certain scenarios, it is essential to follow specific guidelines to ensure safety and effectiveness. Copper remains the preferred material due to its performance and reliability. By adhering to best practices and using the appropriate materials, homeowners and electricians can ensure that their electrical systems are safe and properly grounded.

Key Points to Remember:

Aluminum wiring can be used for Grounding Electrode Conductors to metallic water service pipes within 5 feet of where they enter the house. Aluminum wire cannot be used within 18 inches of the earth for grounding purposes. Copper is generally preferred for grounding due to its better conductivity and reliability.