How to Design Custom Power Busbars: Current Rating, Size & Hole Patterns

ByWei

Why Power Busbar Design Matters

A poorly designed power busbar can lead to:

  • Excessive heat
  • Voltage drop
  • Loose connections
  • Shortened equipment life

That’s why current rating, size, and hole pattern design are critical from the start.

Copper busbar installed inside an electrical control panel or switchgear cabinet

1. Power Busbar Current Rating

The current rating determines:

  • Busbar cross-section size
  • Material choice (copper vs aluminum)
  • Temperature rise limits

General Guidelines

  • Copper busbars carry higher current in smaller size
  • Aluminum busbars require larger cross-sections
  • Ambient temperature and ventilation must be considered

👉 High-current applications often use multiple parallel busbars instead of a single thick bar.

2. Choosing the Right Busbar Size

Busbar size is defined by:

  • Thickness
  • Width
  • Length

Design Considerations

  • Space inside the cabinet or switchgear
  • Mechanical strength
  • Bending requirements
  • Mounting method

Flat rectangular busbars are the most common shape for power distribution.

3. Hole Patterns & Machining Accuracy

Hole design directly affects:

  • Electrical contact quality
  • Assembly speed
  • Long-term reliability

Key Points

  • Hole diameter must match bolt size
  • Hole spacing must align with breakers and terminals
  • Countersunk or tapped holes may be required
  • Tight tolerances prevent misalignment during installation

At CARSAI, hole patterns are CNC-machined to ensure repeatable accuracy.

4. Copper vs Aluminum for Power Busbars

MaterialAdvantagesTypical Use
CopperHigh conductivity, compact sizeSwitchgear, control panels
AluminumLightweight, cost-effectiveLarge power cabinets

Surface treatments like tin plating improve corrosion resistance and contact stability.

5. Custom Power Busbar Manufacturing Process

Our typical process includes:

  • Engineering review of drawings
  • Material selection
  • CNC drilling, milling, tapping
  • Bending and forming
  • Surface finishing (tin plating if required)
  • Final inspection before shipment

❌ We do not manufacture laminated or enclosed busbar trunking systems.

📩 Need Help Designing a Custom Power Busbar?

Share your current rating, application, and layout.
Our engineers will help optimize your busbar design for performance and cost.

👉 Contact us today for custom power busbar support