Introduction

A busbar usually gets attention only after something goes wrong.

Overheating inside a panel. Voltage drops nobody expected. Discoloration near joints. Sudden shutdowns in high-load systems. In many cases, the root problem isn’t manufacturing quality it’s incorrect busbar selection from the beginning.

This happens more often than people think.

A busbar may look like a simple metal strip, but selecting the wrong material, size, plating, or insulation can create serious performance issues later. And once the system is operational, fixing those mistakes becomes expensive.

We’ve seen projects where undersized busbars caused excessive heat within months. In other cases, poor joint design increased resistance and reduced equipment life. Sometimes the issue is even simpler  the wrong material for the environment.

There is a bright side to the fact that many of these problems can be avoided.

This article will explain some of the more prevalent errors that occur during the process of selecting busbars and why these errors occur and how they can be avoided before they cause problems in the electrical system.

What Is A Bus Bar?

A bus bar is an electrical conductor used in a variety of applications, including within electrical distribution panels, switchgears, substations, EV battery systems, and various types of manufacturing equipment. A busbar is the main source for current to flow from the incoming power supply to outgoing circuits.

Bus bars are most often constructed of:

• Copper

• Aluminum

• Tinned copper

• Insulated or sleeved conductors

Bus bars are so popular because they offer the following:

• Superior current capacity

• Space-efficient distribution of electrical power

• Low voltage drops

• Ease of expansion within the system

• Greater reliability than traditional cabling

The Importance of Choosing the Correct Busbar

It’s critical to choose the right busbar, every reason mentioned above has a major impact on how well the busbar will perform in your system.

When a busbar is selected properly, it enhances:

• The overall efficiency of the system

• The management of heat

• The safety of the operation

• The life of the equipment

• The reliability of the maintenance

When a busbar is poorly selected, you may experience the following:

• High temperature rise around the busbar

• Poorly made connections

• Loss of power

• Oxidation (rust) or corrosion of the busbar

• Frequent forced shutdowns

• Potential for fire (in extreme cases)

Also, once a panel is installed, unless the proper busbar was installed, the replacement of the busbars will result in downtime for your panel, redesigning the panel, and additional labor costs.

Therefore, engineers who have experience will take into consideration more than just basic measurements of dimensions.

Mistakes Made with Busbar Ratings

1. Choosing Busbar Size Based Only on Current Rating

 Busbar ratings should not be solely based on ampere rating, as this is one of the most frequent mistakes made.

There are still many manufacturers that are solely using ampere charts to determine busbars from actual operational experience.

Two systems carrying equal current may have different sizes for their busbars based on the following:

• Ambient Temperature

• Ventilation

• Enclosure Type

• Duty Cycle

• Harmonics

• Load Variation

A bus bar may still function properly when smaller than required, but if the bus bar overheats, what can happen?

• Faster insulation degradation

• Joint resistance increases

• Copper oxidation is increased

• Energy loss increases

• Limited life of electrical devices.

To reduce chances of overheating, examine the following:

• Current Carrying Capacity

• Temperature Rise

• Short-Circuit Withstand Capability

• Derating Factors

By increasing the thickness of the busbar slightly, you could prevent many failures in the future.

2. Ignoring Short-Circuit Strength

Many buyers focus only on continuous current.

But during a fault condition, the busbar experiences massive electromagnetic force for a short duration.

If the mechanical strength isn’t adequate, the busbar may

• Bend

• Crack

• Loosen at joints

• Damage insulators

This becomes critical in the following:

• Switchgear panels

• MCC panels

• Power distribution systems

• Transformer connections

Expert Tip

Always verify:

• Fault current rating

• Peak withstand current

• Support spacing

• Mechanical reinforcement

A busbar that handles normal current may still fail during a short circuit.

3. Choosing the Wrong Busbar Material: Copper vs. Aluminum

This common problem comes up in several projects, with both types of material being able to achieve good performance if applied properly.

Copper busbars

Advantages/Pros

• Very high conductance

• Compact size

• Very strong mechanical properties and high strength

• High reliability for mission-critical systems

Disadvantages/Cons

• More expensive than aluminum

• Significantly heavier than aluminum

Aluminum busbars

Advantages/Pros

• Less expensive than copper

• Lightweight compared to copper

• Well suited to use in large distribution systems

Disadvantages/Cons

• Have lower conductivity than copper; therefore, require a larger cross-section

• More susceptible to damage during use as a result of handling

What is the most common mistake?

Using aluminum busbars where compact size and high conductivity were critical or using copper where aluminum would provide lower overall project costs without affecting performance.

How do you properly select your type of busbar material?

• Determine the load requirements

• Examine your budget.

• Take the space constraints into consideration.

• Think about environmental issues that might be present.

• Have a long-term expectation for maintenance

Many times aluminum busbars can perform very well if they are properly designed for industrial applications.

What Are the Causes of Busbar Failures?

Heating, an unsatisfactory joint design, improperly sized conductors, connection issues, corrosion, and/or poor material selection generally cause busbars to fail. Most busbars fail due to not being matched appropriately to their electrical/environmental characteristics.

4. Bad Joint Design and Poor Connections

Even a good busbar can still fail due to poor work done at a joint. The joint area is most often the hottest area in any kind of system.

Examples of connection issues include the following:

• Uneven Contact Surfaces

• Improper Tightening of Torque/Pressure

• Improper plating of connector surfaces

• Oxidation Deposits

• Loose Bolt Connections

Highly resistant joints continuously build up heat due to their resistance. Eventually the heat from a joint becomes apparent by

• Burnt Areas of the Joint

• The color of the joint has changed

• Area of insulation damage at a joint

• A hot spot when thermally scanned

What to Do to Prevent the Joint Connection Issues:

• Ensure Proper Surface Preparation

• Use Proper Torque Values

• Make Sure the Contact Areas of All Surfaces are Flat

• Use Good Quality Fasteners

• Consider Using Tin Plating to Prevent Corrosion

This is extremely important in high-current applications.

5. Not Taking Into Account Environmental Conditions

Busbars don’t work in the best environment.

Real-World Conditions You will most likely face the following:

• High humidity

• Dust

• Chemical exposure

• Changes in the outside temperature

• Corrosion from the coast

If you never take into consideration the environment, you will severely reduce the life of the busbars.

Example:

Copper busbars in a humid environment oxidize quickly, which increases resistance in the busbars over time.

In these types of situations tin plated copper busbars typically excel exceptionally better than other alternatives.

What Do Experts Recommend:

To help avoid problems in harsh environments, you should consider the following:

• Plating with Tin

• Use of Insulated Sleeving

• Provide Adequate Ventilation for Equipment Enclosures

• Use of Corrosion Resistant Fasteners

Environmental compatibility is much more important than what most people understand.

6. Developing a Busbar Insulator Incorrectly

Many applications require that the busbars be insulated to help with safety reasons and also for compact designs.

The insulation is too often not considered/designed correctly.

Problems associated with improperly insulated busbars consist of:

• Low heat resistance

• Poor dielectric performance

• Cracking due to thermal cycles

• Incorrect sleeve thickness

The importance of proper insulation is even more important for the following applications:

• Electric Vehicle Battery Packs

• Compact Switchgear

• Renewable Power Systems

Best Practice

When designing insulated busbars:

Consider the following:

• Voltage Rank

• Operating Temperature Range

• Flame Retardancy

• Mechanical Flexibility

Not every insulation material is rated for applications with high-temperature service conditions.

7. Overlooking Future Load Expansion

A system designed for today’s load may struggle tomorrow.

This is common in

• Commercial buildings

• Data centers

• Manufacturing plants

• Solar power systems

People often select busbars too close to present load requirements.

Then expansion happens.

And suddenly the entire distribution system becomes a limitation.

Smarter Planning

Keep additional capacity wherever possible.

Slight oversizing now is usually cheaper than a complete upgrade later.

Top Benefits of Proper Busbar Selection

The selection of busbar types can improve a power system’s efficiency.

When busbars are selected correctly, power distribution efficiencies are improved, the risk of overheating is reduced, equipment’s life expectancy is lengthened, the dangers of electric shock are reduced, and maintenance costs are minimized.

The main benefits of choosing the appropriate busbar for a power system are the following:

• Power losses are reduced

• Improvement in thermal performance

• Ensures reliable current distribution

• Less downtime

• Increased safety

• Longevity for system

A Guide on the Selection of Busbars

Step 1. Determine Actual Load Requirements

Begin by assessing your present operational current and not just the theoretical loads’ values.

You should take into consideration the following items within your current requirements:

• Peak load

• Continuous load

• Future expansion

• Harmonics

Step 2. Select The Correct Material To Be Used

Copper or aluminum should be selected according to your current conducting needs, your budget, installation area, and weight restrictions.

Generally copper properties will be better suited for compact applications.

In contrast, when large applications are present and you have to be price conscious, it may make sense to select aluminum.

Step 3. Thermal Assessment

Calculating how much heat will be produced by the busbar and whether that amount will be within its safe operating temperature must be done.

Step 4. Calculate Short Circuit Ratings

A short circuit rating will need to be done to ensure proper fault withstand and also to ensure a proper rating is provided by the manufacturer/supplier of the busbars being used for that system.

Step 5: Joint Design Evaluation

It is important to have the right joint design because having a good joint design can improve reliability and reduce resistance.

To support achieving good joint design, we consider the following:

• Surface Finish

• Contact Pressure

• Plating Quality

• Hardware Quality

Step 6: Environmental Considerations

If you are working with a busbar outdoors, in humid conditions or in an environment that has a lot of corrosive chemicals, you may need to take extra measures to protect the busbar. These include:

• Tin Plating

• Sleeving

• Coatings

• Improved Enclosure Design

Expert Suggestions for Long-Lasting Busbar Reliability

Here are some solid guidelines from manufacturers who have had years of experience supplying busbars:

Install Thermal Scanning Equipment During Maintenance

Infrared thermographic imaging will help identify heat-producing problems before they become catastrophic.

Consider surface finish

The finish on a busbar plays a critical role in conducting electricity. The better the finish, the better the connection.

Maintain Proper Torque Values

Both overtightening and undertightening connectors can result in poor performance.

Fabricate with Quality

Precision bending, punching, and plating help with accurate installation and better-performing busbars.

Standardization is key

Standardized designs for a busbar will streamline maintenance and allow for easier future expansions to be made upon.

FAQ

What is the main cause of busbar overheating?

Some of the main causes of overheating of busbars include undersized busbars, loose connections, poor contact, and excessive loads through the busbars.

Is a copper or aluminum busbar better?

Copper has superior conductivity and smaller dimensions than aluminum, but aluminum is lighter than copper and less expensive. It depends on the intended application as to which type should be used.

Why are copper busbars used with tin?

Tin plating increases corrosion resistance and helps maintain better contact over time.

How do you determine what size busbar to use?

With proper design and maintenance, busbars can operate reliably for decades.

Can an aluminum busbar be used instead of a copper busbar?

In many instances, aluminum busbars can be used instead of copper busbars. To make this successful, the engineer must design the busbars to be equivalent in size for their carrying capacity, and aluminum requires larger cross sections and adequate jointing and electrical connections than copper.

What types of industries most commonly use busbar products?

Busbar products will typically be found in electrical distribution equipment, such as

• Electrical Panelboards

• Switchgears

• EV Battery Packs

• Renewable Electrical Energy Systems

• Data Centre

• Industrial Machinery

How long do busbars last?

The lifespan of busbars is determined by the construction and installation of those systems.

If properly designed and maintained, busbars will perform satisfactorily for many years.

Final Thoughts

The majority of the time, busbars fail due to the selection process, not because of defective materials.

Most of the time, failures occur due to neglect of important criteria when selecting design parameters.

Criteria such as temperature increases, joint quality, fault current, ventilation, and future load growth all greatly affect long-term performance.

A well-designed busbar system will perform its functions well for years without any problems, indicating good engineering practices.

Therefore, if installing or upgrading an electrical distribution system, consider spending extra time on selecting a busbar system rather than just considering it a standard commodity item.

If you are looking for a custom-built copper/aluminum busbar solution for your switchgear, electric vehicle, or industrial power distribution system, looking to work with an experienced busbar manufacturer is the best decision you can make to eliminate potential design and performance issues later on down the line.

Consider visiting Adinath Enterprises for custom solutions.