Kingdta manufactures heavy copper PCBs from 3 oz to 20 oz copper weight for power distribution boards, bus bars, EV charging equipment, and industrial power electronics. Our specialized etching and plating process maintains trace geometry accuracy at high copper weights.
What Is a Heavy Copper PCB?
A heavy copper PCB uses copper foil or plating heavier than the standard 1 oz (35 μm) used in conventional PCBs. Heavy copper is typically defined as 3 oz (105 μm) or greater, with extreme copper boards reaching 20 oz (700 μm) for high-current bus bar applications.
The primary benefit of heavy copper is current-carrying capacity. A 1 oz copper trace 1mm wide carries approximately 1.5A before reaching a 10°C temperature rise. The same trace in 3 oz copper carries 3.5A, and in 10 oz copper carries 8.5A. For power distribution boards handling 50–200A, heavy copper is the only practical solution.
Heavy copper PCBs also provide improved thermal performance (thicker copper conducts heat more effectively), better mechanical strength, and improved reliability in thermal cycling due to lower thermal resistance in the copper traces.
Technical Specifications
Key Advantages
High Current Capacity
20 oz copper traces carry 200A+ continuous current — enabling compact power distribution without external bus bars.
Reduced Thermal Rise
Thick copper traces have lower resistance, reducing I²R heating and allowing higher current density.
Integrated Bus Bars
Replace external copper bus bars with PCB-integrated copper traces, reducing assembly complexity and cost.
Improved Thermal Management
Thick copper layers conduct heat laterally, spreading thermal load across the board and reducing hot spots.
High Mechanical Strength
Heavy copper adds rigidity to the board, reducing flex and vibration-induced fatigue in high-vibration environments.
Mixed Copper Weight
Combine heavy copper power layers with standard 1 oz signal layers in a single multilayer board for mixed power/signal designs.
Where It's Used
EV Charging
EVSE power distribution boards, on-board chargers
Power Electronics
Motor drives, inverters, DC-DC converters
Industrial
Welding equipment, induction heating, UPS systems
Renewable Energy
Solar inverters, wind turbine converters
Automotive
Battery management systems, EV powertrain
Aerospace
Power distribution units, satellite power systems
Defense
Radar power supplies, EW transmitters
Telecom
Base station power supplies, rectifiers
Why Choose Kingdta for Heavy Copper?
- Specialized heavy copper etching process maintains trace geometry accuracy up to 20 oz
- Mixed copper weight capability: heavy copper power layers + standard signal layers in one board
- Current-carrying capacity calculation and thermal simulation included with quote
- IPC-2152 current capacity standards applied to all heavy copper designs
- Full turnkey service: heavy copper PCB fabrication + power component assembly
- Experience with EV, industrial, and aerospace high-current applications
Frequently Asked Questions
What is the maximum current a heavy copper PCB can carry?
With 20 oz copper and appropriate trace width, a heavy copper PCB can carry 200A+ continuous current. The actual current capacity depends on copper weight, trace width, ambient temperature, and acceptable temperature rise. We calculate current capacity per IPC-2152 for every heavy copper design.
Can you mix heavy copper and standard copper in the same board?
Yes. We regularly manufacture boards with heavy copper (3–10 oz) on power layers and standard 1 oz copper on signal layers. This allows high-current power distribution and fine-pitch signal routing in a single board. The stackup design requires careful consideration of the copper weight difference between layers.
What is the minimum trace width for heavy copper?
Minimum trace width increases with copper weight due to the etching process: 0.5mm for 3 oz, 0.8mm for 6 oz, and 1.0mm for 10 oz+. Tighter widths are possible with special etching chemistry at additional cost.
Do you offer heavy copper on aluminum base?
Yes. We manufacture heavy copper on aluminum base (MCPCB) for applications requiring both high current capacity and high thermal conductivity. This combination is common in EV charging and power module applications.
Related PCB & PCBA Types
10 oz Heavy Copper PCB for 150kW DC Fast Charger Power Distribution
A US-based EV charging infrastructure company developing a 150kW DC fast charger — requiring a power distribution PCB to route 400A at 375V DC from the rectifier stack to the output connectors.
The Problem
The customer's original design used external copper bus bars bolted to a standard PCB. This approach required 14 separate bus bar segments, 28 bolted connections, and a dedicated assembly jig — adding $47 in material cost and 35 minutes of assembly time per unit. The bolted connections also showed 0.3–0.8 mΩ contact resistance variation, causing unacceptable output voltage variation between units.
Key Challenges
- 400A continuous current at 375V DC — requiring 10 oz copper traces with 8mm minimum width
- Creepage distance ≥8mm between 375V DC and 24V control circuits on the same board
- Board temperature rise ≤15°C at 400A in 40°C ambient — requiring thermal simulation validation
- UL 2202 and IEC 61851 certification requirements for EV charging equipment
- Board size 380mm × 280mm — requiring precise copper etching uniformity across large panel
Our Solution
We designed a 4-layer heavy copper board with 10 oz copper on layers 1 and 4 (power distribution) and 1 oz copper on layers 2 and 3 (control signals). The 375V DC bus traces were routed with 10mm width and 10mm creepage to the 24V control circuit. Thermal simulation using the actual copper geometry predicted a 12°C temperature rise at 400A — within the 15°C specification. We implemented a modified etching process with reduced etch factor compensation for the 10 oz copper to maintain trace width accuracy within ±0.1mm across the 380mm × 280mm panel. All boards were 100% tested for isolation resistance (>1GΩ at 500V DC) and continuity before shipment.
Results & Outcomes
"Replacing the bus bar assembly with a heavy copper PCB was a significant design change, but Kingdta's engineering team made it straightforward. The thermal simulation they provided before production accurately predicted what we measured, and the cost savings paid for the design change in the first 200 units."
Hardware Engineering Manager, EV Charging Company — Austin, TX, USA