What Size Busbar Do I Need​

When designing an electrical system, one of the most common engineering questions is: What size busbar do I need?
Choosing the correct busbar size is critical for safety, efficiency, and long-term reliability, whether you are working with an electric busbar, Battery Busbar, or a complete busbar power system.

This guide explains how to select the right busbar based on current, material, installation conditions, and application requirements.

What Is a Busbar?

A busbar (also known as an electrical bus bar or bus bar electric) is a solid conductor used to distribute power within an electrical panel, power cabinet, or battery system. Common materials include Copper Busbar and aluminium busbar, both widely used in modern busbar systems.

Key Factors That Determine Busbar Size

To answer the question “What size busbar do I need?”, you must consider several technical factors.

1. Rated Current (Amperage)

The most important factor in selecting a busbar size is the rated current.

Higher current requires a larger cross-sectional area (width × thickness) to prevent overheating and excessive voltage drop.

2. Busbar Material Selection

Copper Busbar

• High electrical conductivity

• Smaller size for the same current

• Common in Battery Busbar, electrical panel bus bar, and busbar power applications

Aluminium Busbar

• Lightweight and cost-effective

• Requires a larger size than copper for the same current

• Often used in large busbar electrical systems

Typically, an aluminium busbar needs about 1.5–1.7 times the cross-sectional area of a copper electrical busbar.

3. Installation Environment

Busbar size is also affected by:

• Enclosed or open electrical panels

• Natural or forced air cooling

• Ambient temperature

Poor ventilation requires a larger electric busbar to limit temperature rise.

4. Application Type

Different applications place different demands on busbar sizing:

• Battery busbar: must handle high peak and surge currents

• Busbar power system: designed for continuous current flow

• Electrical panel bus bar: space constraints and insulation requirements

• Custom busbars: optimized for specific layouts and loads

Typical Copper Busbar Size Reference (Natural Cooling)

Note: Actual sizing may vary depending on installation conditions and safety standards.

How to Select the Right Busbar Size

A simplified selection process:

1. Determine maximum continuous current

2. Choose copper or aluminium busbar

3. Evaluate cooling and enclosure conditions

4. Consider future expansion and safety margins

5. Decide whether standard or custom copper busbar is needed

For complex systems, laminated busbar or insulated Flexible Busbar solutions may be preferred.

Why Proper Busbar Sizing Matters

Incorrect busbar size can lead to:

• Excessive heat generation

• Power loss and voltage drop

• Reduced service life

• Potential safety hazards

Correct sizing ensures your busbar system operates efficiently and safely over time.

So, what size busbar do I need?
The answer depends on current rating, material type, installation environment, and application requirements.

By selecting the correct busbar size, you improve system efficiency, reliability, and safety—especially in busbar power, battery busbar, and electrical panel bus bar applications.