What Is C11000 Copper Busbar?
C11000 copper busbar, fully known as Electrolytic Tough Pitch (ETP) copper, contains 99.9% pure copper with a small, controlled amount of oxygen (0.02-0.04%). This composition gives it an electrical conductivity of ≥101% IACS, making it the highest conductivity among all practical engineering metals.
5 Core Factors That Determine C11000 Copper Busbar Ampacity
Cross-sectional area (most important): Ampacity increases with larger width and thickness. Doubling the area does not double the current, but the relationship is close.
Allowable temperature rise: Standard design uses 65°C maximum operating temperature above a 35°C ambient. Higher ratings (105°C) are possible with special insulation.
Ambient temperature: For every 10°C above 35°C, reduce ampacity by 5-10%. If your switch room reaches 45°C, apply a 0.88 derating factor.
Installation method: Bare busbars in open air cool best. Busbars inside enclosed cabinets lose 10-15% capacity. Multiple busbars stacked together also derate.
- AC vs. DC: For DC applications, add 5-8% to the AC ampacity value due to the absence of skin effect.
C11000 Copper Busbar Ampacity Quick Reference Table (35°C Ambient, 65°C Operating)
Below is a practical ampacity table for flat C11000 copper busbars. These values are based on ASTM B187 standards and our factory testing.
| Width (mm) | Thickness (mm) | Cross-section (mm²) | Ampacity (Amps AC, 50/60Hz) |
|---|---|---|---|
| 20 | 3 | 60 | 180 A |
| 20 | 5 | 100 | 250 A |
| 25 | 5 | 125 | 300 A |
| 30 | 5 | 150 | 370 A |
| 30 | 10 | 300 | 600 A |
| 40 | 5 | 200 | 460 A |
| 40 | 10 | 400 | 750 A |
| 50 | 5 | 250 | 550 A |
| 50 | 10 | 500 | 900 A |
| 60 | 10 | 600 | 1050 A |
| 80 | 10 | 800 | 1350 A |
| 100 | 10 | 1000 | 1600 A |
| 120 | 10 | 1200 | 1850 A |
| 120 | 20 | 2400 | 2800 A |
How to Calculate Ampacity for Custom Size C11000 Copper Busbar
For non-standard sizes, use this empirical formula based on industry practice:
Ampacity (Amps) = Cross-sectional area (mm²) × Current density coefficient (A/mm²)
| Thickness Range | Recommended Current Density Coefficient |
|---|---|
| 3-6 mm (thin, good cooling) | 3.5 – 4.0 A/mm² |
| 6-15 mm (medium) | 3.0 – 3.5 A/mm² |
| 15-30 mm (thick, limited cooling) | 2.5 – 3.0 A/mm² |
Example calculation: For a custom size 45mm × 8mm copper busbar:
- Cross-sectional area = 45 × 8 = 360 mm²
- Thickness 8mm falls in medium range → use 3.2 A/mm²
- Estimated ampacity = 360 × 3.2 = 1152 Amps
C11000 Copper Busbar vs. Aluminum Busbar
| Property | C11000 Copper | Aluminum (6061 or 1350) |
|---|---|---|
| Conductivity (% IACS) | ≥101% | 61-62% |
| Ampacity for same size | Baseline | Only 61% of copper |
| Size needed for same ampacity | Baseline | 1.5× larger cross-section |
| Weight for same ampacity | Baseline | ~0.5× lighter |
| Thermal expansion | 17 ppm/°C | 23 ppm/°C (higher creep risk) |
| Surface oxidation | Conductive (CuO) | Non-conductive (Al₂O₃) – increases resistance |
To achieve the same ampacity as copper, aluminum must be 50% larger in cross-section. While lighter, aluminum suffers from creep (loosening connections) and surface oxidation that increases contact resistance over time. For critical applications like switchgear, MCCs, and EV infrastructure, C11000 copper busbar is the reliable, long-term choice.
How We Ensure Every C11000 Copper Busbar Delivers Rated Ampacity
| Test | Equipment | Standard | Frequency |
|---|---|---|---|
| Conductivity | Eddy current sigmascope | ≥101% IACS | Every batch |
| Dimensions | Hexagon CMM / precision calipers | ±0.1mm (width/thickness) | 100% |
| Hardness | Rockwell tester | HV 60-85 (half-hard temper) | Every batch |
| Surface finish | Visual inspection | No scratches, pits, or burrs | 100% |
| Plating thickness (if applicable) | XRF analyzer | Tin 3-8μ / Silver 5-15μ | Every batch |
| Salt spray test | ASTM B117 chamber | ≥96 hours no red rust | Weekly |
Manufacturing Capability
Key Equipment:
- CNC shearing machine (thickness up to 30mm, width up to 250mm)
- AMADA CNC punching press (hole tolerance ±0.1mm)
- ACCURL CNC press brake (bending length up to 3000mm, ±1° tolerance)
- Automatic in-house plating line (tin / silver / nickel, up to 4000mm length)
- CMM inspection (Hexagon – dimensional accuracy verification)
Production Capabilities:
- Maximum length: Up to 6000mm per piece
- Thickness range: 3mm – 30mm
- Width range: 10mm – 250mm
- Custom shapes: L-bend, Z-bend, U-bend, and custom angles
Export-Grade Packaging
| Layer | Material | Purpose |
|---|---|---|
| Inner wrap | VCI (Vapor Corrosion Inhibitor) film | Prevents oxidation – VCI molecules coat all surfaces |
| Interleaving | Kraft paper + foam sheet | Prevents scratching between layers |
| Bundling | Steel straps (3-5 per bundle) | Secures bundles together |
| Pallet | Heat-treated plywood (IPPC certified) | No fumigation needed for customs |
| Outer protection | Corner protectors + stretch wrap | Prevents pallet damage during loading |
For bent or custom shapes, we add custom foam cradles to prevent deformation during transit. For air freight or courier (DHL/FedEx/UPS), we use heavy-duty cardboard boxes with internal foam padding.
FAQ
Q1: How many amps per square millimeter can C11000 copper busbar carry?
Typically 2.5 to 4 amps per square millimeter (A/mm²). This coefficient depends on thickness and cooling conditions. Thin busbars (e.g., 3mm) dissipate heat well and can use 4A/mm². Thick busbars (e.g., 20mm) retain heat and should use 2.5A/mm². Always apply ambient temperature derating for final selection.
Q2: How many amps can a 100x10mm C11000 copper busbar carry?
Approximately 1600 amps under standard conditions (35°C ambient, 65°C operating). This matches our reference table above. For DC applications, add 5-8% (up to 1728A). For enclosed cabinets with poor ventilation, reduce by 10-15% (down to 1360-1440A).
Q3: Is there an ampacity difference between C11000 and C10200 (oxygen-free) copper busbar?
No – both have essentially identical ampacity. Both grades achieve ≥100% IACS conductivity. C10200's advantage is hydrogen embrittlement resistance in high-temperature hydrogen atmospheres (brazing furnaces), not current carrying capacity. For 95% of electrical applications, C11000 delivers the same performance at much lower cost.
Q4: How can I increase the ampacity of my C11000 copper busbar?
The most effective methods are surface plating and improving airflow. Tin or silver plating reduces contact resistance, lowering temperature rise and increasing ampacity by 5-10%. Splitting one thick busbar into two thinner bars with a gap between them doubles the cooling surface area, significantly increasing total ampacity.
Q5: Does bending C11000 copper busbar reduce its ampacity?
With proper bend radius (≥1.5× thickness), the reduction is negligible (<2%). If the bend radius is too tight, micro-cracks and work hardening can increase local resistance by 5-8%. For high-current applications (>1000A), we recommend round-edge busbars to avoid stress concentration at corners.
Q6: How much does surface oxidation reduce copper busbar ampacity?
Answer: Light oxidation has minimal effect (<3%) on bulk ampacity, but severe corrosion affects connections. Copper oxide (CuO) is still conductive. The real problem is increased contact resistance at joints, which causes localized heating. Solution: apply conductive grease at connections or specify tin-plated C11000 copper busbar.
My project needs 1800 amps. What size C11000 copper busbar should I choose?
Answer: A single 120x10mm busbar or two parallel 80x10mm busbars. Single 120×10mm provides ~1850A. If space is limited, two 80×10mm busbars installed with a gap provide approximately 1700-2000A total, with better flexibility for routing. Provide your specific installation conditions, and we can calculate precisely.
Q8: Do you offer C11000 copper busbar with custom bending and punching?
Yes – we offer L-shape, Z-shape, U-shape, and custom angles. Our CNC press brake achieves ±1° angle tolerance. Hole punching includes round holes (4-20mm diameter) and slotted holes (6×12mm to 10×25mm). Send your drawing (PDF, DWG, or DXF), and we will provide a quote for fabrication-ready busbars.
Q9: How do you package C11000 copper busbar for ocean freight to prevent corrosion?
VCI film + IPPC-certified wooden pallets + full stretch wrap. Every busbar is first wrapped in VCI (Vapor Corrosion Inhibitor) film, which releases molecules that settle on all metal surfaces, blocking moisture. Bundles are then strapped to heat-treated plywood pallets (no fumigation needed) and fully stretch-wrapped with corner protectors. This system prevents rust for 60+ days at sea.
Q10: What is the MOQ for custom size C11000 copper busbar?
50 pieces for custom sizes, 10 pieces for standard sizes, and no MOQ for samples. Standard sizes (from our die library) ship with 10-piece MOQ. For customer-specific widths, thicknesses, or lengths, MOQ is 50 pieces. Samples (any size, any shape) have no MOQ – we support prototype orders before mass production.
