Copper Purity Grades Explained: 99.90% vs 99.99% vs 99.999%
When purchasing bulk copper cathode or wire, one of the most critical factors that influences pricing, applications, and buyer confidence is the copper’s purity grade.
Many first-time importers assume copper is simply “pure or not” — but in reality, small differences in purity levels can dramatically impact performance, export value, and compliance with your industry’s specifications.
In this guide, we’ll break down exactly what 99.90%, 99.99%, and 99.999% copper mean — and how to select the right purity for your project or resale market.
Why Copper Purity Is Critical in Global Trading
Copper’s industrial value is heavily tied to its electrical conductivity, corrosion resistance, and mechanical stability.
The higher the purity level, the better it performs for:
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Electrical transmission and wiring
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Renewable energy infrastructure (solar, wind, EV)
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Manufacturing of electronics & semiconductors
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High-end construction and industrial projects
Small variations in purity can affect:
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Price per metric ton
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End-use suitability
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Market demand
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Customs classification and duties
99.90% Purity (Grade C or Industry-Standard Grade)
✅ Purity Level: 99.90% Copper
✅ Common for:
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Construction-grade wiring
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Plumbing & piping
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Industrial grounding wires
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Some export markets with relaxed standards
✅ Pricing:
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More affordable than higher grades
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Sufficient for basic conductivity needs
✅ Inspection:
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Still requires SGS verification to ensure proper chemical composition.
99.99% Purity (Grade A — LME Standard Copper)
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✅ Purity Level: 99.99% Copper (LME-registered Grade A Copper Cathode)
✅ Common for:
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Electrical grid infrastructure
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Renewable energy projects
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Power cables
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Export contracts tied to LME standards
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International tenders
✅ Pricing:
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Global trading benchmark
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Widely used in high-volume copper trading contracts
✅ Why Many Buyers Choose 99.99%:
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Meets global compliance
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Compatible with most export/import regulatory frameworks
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Attractive for long-term projects
99.999% Purity (5N Ultra High Purity)
✅ Purity Level: 99.999% Copper (known as “5N” or Ultra High Purity Copper)
✅ Common for:
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Precision electronics manufacturing
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Semiconductor production
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Medical-grade equipment
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Specialized military/aerospace applications
✅ Pricing:
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Premium pricing tier
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Limited supply, smaller production runs
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Requires advanced refining processes
✅ Special Considerations:
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Exported mostly in smaller batches
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Heavily regulated purity verification
How Purity Impacts Your Copper Buying Decision
How GRP Partners LLC., Guarantees Purity for Every Shipment
At GRP Partners, purity is non-negotiable. Every shipment is:
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Fully certified by IGAS, SGS or equivalent third-party laboratories.
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Supplied with Certificates of Analysis (COA).
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Fully documented for import/export compliance.
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Backed by detailed Copper Certifications package.
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Delivered export-ready from our Warehouse Facilities.