Earth Grounding Construction Materials
Choosing the right materials for earth grounding systems can be overwhelming with options like copper, aluminum, brass, and various wire types (stranded, solid, bare, covered). However, the length of the conductor is the most critical factor.
Key Principle:
Shorter is Better.
A short conductor can be hundreds of times more effective than a longer, thicker one. In fact, bolting components together (zero length) often outperforms long wire runs.
Material Considerations:
- Copper – The preferred choice due to low resistance, durability, and resistance to oxidation. Suitable for direct burial and long-lasting.
- Brass – Slightly higher resistance (5% more than copper) but performs well.
- Aluminum – 20% higher resistance than copper and prone to oxidation, making it less ideal for grounding.
Recommendation: Use copper or brass for most applications. Copper is cost-effective and reliable over time.
Application Tips:
- Tower Grounding – Use conductors with similar current capacity as the tower frame (typically #14 copper or larger). Undersized ground wires can burn out like a fuse during lightning strikes.
- Indoor Equipment Grounding – Smaller wire (#12 to #4) can be used. Choose the largest manageable size for durability.
- Connections – Keep connections tight and clean. Apply anti-oxidant compounds and weatherproofing for long-term performance.
Conductor Types:
- Best Choices:
- Stranded, covered wire (THW, THHN, or welding cable) – Flexible, long-lasting, and resistant to oxidation.
- Solid strap – Excellent but harder to obtain and work with.
- Avoid:
- Bare braided conductors (e.g., coaxial shield) – Prone to oxidation, reducing conductivity over time.
Final Advice:
Don’t overcomplicate the selection process. Use the shortest possible length and a reliable conductor like copper or brass. A simple, well-executed ground system outperforms elaborate designs with excessive wiring.