Copper vs Aluminum Conductors: Complete Comparison
Comprehensive comparison of copper and aluminum conductors for voltage drop, cost, installation, and performance. Make informed material choices for your projects.
Choosing the Right Conductor Material
The choice between copper and aluminum conductors significantly impacts voltage drop, installation cost, long-term performance, and system reliability. Both materials have legitimate applications in modern electrical systems, and understanding their properties helps engineers and electricians make informed decisions. This comprehensive guide compares copper and aluminum across all factors relevant to voltage drop calculations and electrical design.
Historically, copper has been the preferred material for most electrical installations due to its superior conductivity and ease of termination. However, modern aluminum alloys and improved termination techniques have made aluminum an excellent choice for many applications, particularly large feeders where cost savings are substantial.
Electrical Properties Comparison
| Property | Copper | Aluminum |
|---|---|---|
| Conductivity (% IACS) | 100% | 61% |
| Resistance (relative) | 1.00 | 1.64 |
| Weight (relative) | 1.00 | 0.30 |
| Cost per ampacity | Higher | Lower |
| Size for equivalent ampacity | Smaller | ~2 sizes larger |
Voltage Drop Implications
For equivalent voltage drop performance, aluminum conductors must be approximately two AWG sizes larger than copper. For example, where 2 AWG copper would be used, 1/0 AWG aluminum provides similar voltage drop. This size increase must be considered when selecting conduit and planning raceway space.
Copper Advantages
- • Lower resistance = less voltage drop
- • Smaller conduit requirements
- • Easier terminations
- • Higher corrosion resistance
- • Preferred for branch circuits
Aluminum Advantages
- • Significant cost savings
- • Lighter weight for easier handling
- • Economical for large feeders
- • Modern alloys (AA-8000) very reliable
- • Ideal for service entrances
When to Use Each Material
Choose Copper When:
- • Installing branch circuits (NEC typically requires copper for 10 AWG and smaller)
- • Space is limited and smaller conductors are advantageous
- • Corrosive environments are present
- • Terminations will use non-AL/CU rated devices
Choose Aluminum When:
- • Large feeder runs where material cost is significant
- • Service entrance conductors (standard practice)
- • Long distance runs where material cost adds up
- • Weight is a concern (large installations, overhead)
Compare Materials in Your Design
Use our voltage drop calculator to compare copper and aluminum options for your specific application. See the size requirements and voltage drop for each material to make an informed decision.
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