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What is a Busbar and Other FAQs

Busbars are incredible pieces of technology that make complicated power distribution much easier, less expensive and more flexible. This article explores how busbars work and the common questions that people ask when choosing an electrical solution.


What is a busbar?

Busbars, also known as busbar trunking systems, distribute electricity with greater ease and flexibility than some other more permanent forms of installation and distribution. Sometimes spelled bus bar or buss bar, they are often metallic strips of copper, brass, or aluminum that both ground and conduct electricity. 

Busbars being used in an industrial environment

Different coating materials provide different conductivity limits and variations in the length of a product’s useful life. Busbars can also come in a multitude of shapes and sizes which affect the ampacity of the product. The word ampacity refers to the maximum amount of electric current a conductor can carry before sustaining critical levels of deterioration.

Busbars can either be fully enclosed or designed with a continuous access open-channel. Fully enclosed busbars provide similar benefits of reduced installation time and increased performance while supporting higher ampacities.

Other reasons that busbars are popular:

Reduced facility costs because less construction labor means installation is less expensive and there are no costly changes and outside labor costs for electrical specialists.

Faster installation because building projects are up and running faster plus the ability to add, remove or relocate power easily and quickly with no downtime.

Flexibility for the future because some plug-in units can be disconnected and reconnected without de-energizing, require no routine maintenance and are faster and less costly for expansion or remodeling.

Environmentally friendly because busbars often require fewer installation materials and plug-in outlets are reusable and re-locatable.

Recent advancements to the structural integrity of busbar systems have proven changing the shape of the copper busbar greatly improves the efficiency, exposing more of the copper surface area and increasing a balanced electrical flow while decreasing its ampacity.


Where are busbars used?

Busbar systems are used to safely implement three-phase power distribution systems, often in large environments. Busbars are found in

  • Factories
  • Data centers
  • Retail facilities
  • Laboratories
  • Hospitals
  • Universities
  • Technology settings

This image highlights what a busbar looks like in a manufacturing setting, where flexible power distribution is essential. Work stations and machinery moves, and the electrical source should be flexible enough to follow. 

Winar illuminated busway

Busbars range greatly in size and the size is dependent on the use. Common commercial and industrial busbars sizes are:

40, 50, 60, 100/160, 225, 250, 400, 600/630, 800, 1000, and 1200/1250 amps

They can also be used as housing for expandable track lighting which runs from one single power supply.

For applications in which higher ampacity is required, high power busbar trunking systems can provide up to 6300 amps. Common high power busbar amperages include:

630, 800, 1000, 1250, 1600, 2000, 2500, 3200, 4000, 5000, and 6300 amps


What is a copper busbar?

Copper is a common conductive metal used in busbars and many electrical utilities around the world. Copper is chosen for it’s resilience to higher temperatures, providing extra security during short circuit situations.  

Other benefits provided by the use of copper are:

  • High conductivity
  • Resistance to damage
  • Higher performance in clamped joints
  • Lower coefficient of linear expansion
  • Long lifespan
  • High recovery value
  • Higher modulus of elasticity
  • The surface of copper naturally oxidizes forming a thin hard layer on the surface which remains conductive. Exposed aluminum surfaces also form an oxidized film. However, this film is not conductive and leads to long term reliability issues with joints.

For an (extremely) in-depth technical analysis on the applications and conductivity levels of copper busbars, visit this study by the Copper Alliance Association.


Why are U-shaped busbars popular?

U-shaped busbar systems deliver continuous and reliable connections to power while maximizing the potential tappable locations. The U-shape supports even weight distribution; mitigating any distortion resulting from excessive force. 

This system enables simple expansion, reconfiguration, or relocation operations and the shape applies continuous pressure to every joint creating a solid connection and eliminating the need for routine maintenance.

U-shaped electrical bus bars

In the diagram above, (N) is used to signify neutral and (G) is used to signify ground. L1, L2 and L3 reflect Phase A, Phase B and Phase C, respectively.


What is the cost of ownership?

Cost of ownership following installation is often low because overhead systems remove the need for construction and electrical work. When a new connection to power is needed, an additional plug-in unit can be inserted anywhere along the existing open-access slot. This diagram illustrates how the Starline Busway is installed with expansion in mind.

Busbar expansion and ownership costs

Plug-in units can be customized to your needs enabling specific expansion projects and simple relocation. Relocating the Busway track is so simple that it can be completed by in-house employees rather than electricians. Standard corporate electrical systems often cost more to maintain than the cost of initial implementation.


Do busbars promote energy efficiency?

Busbars can be used to conduct any form of electrical current from any type of grid.

A 2009 study done by McKinsey & Co. states that homes and businesses collectively pay $130 billion per year on energy that powers standby appliances. Renewable energy integration can be difficult when using below-ground electrical wiring. Overhead or above ground electrical systems are much easier to restructure and reconfigure for optimal efficiency.


Is power monitoring available?

Analysts continue to rank energy efficiency as a top concern of industrial organizations and corporate teams. However, the truth is, you simply can’t improve something, especially energy efficiency, if you’re not measuring it.

According to Energy Star, energy efficiency projects often pay for themselves in energy savings, but if you don’t know how much energy you’re using, and how much it costs, it is very difficult to justify new technologies and best practices or assess the savings of those new methods. Without a baseline, and then continued measurements, it is impossible to determine where to optimize, to evaluate the results of the optimizations, or to show the improvements to management, government agencies, or customers.

You also need to be able to identify energy consumption peaks and lows, and determine how they relate to operations or key internal and external events such as marketing campaigns, accounting cycles, or changing weather patterns to enable you to adequately plan for these events.

By measuring power usage, you can:

  • Identify current power costs and set a baseline
  • Identify potential cost savings and set goals
  • Implement efficiency improvement projects
  • Continuously measure to determine success

Some busbars offer power monitoring. The Starline Critical Power Monitor (CPM) is one solution. This monitoring solution can be used as a standalone system mounted to electrical panels, or can also be incorporated into busway end feeds and branch-circuit applications to measure the amount of power being drawn.


  • Modular capability for connecting to mains of varying size and specification (voltage and current levels).
  • Modular capability for connecting to branch circuits.
  • 60-1200 amp capacity configurations.
  • Ability to monitor single phase, two phase, three phase, and three phase with neutral.
  • Ability to measure power, power factor, frequency, Volt Amperes, Watt hours, Volts (each phase), current (each phase) current (neutral), reactive power, and temperature. Calculates minimum and maximum values for power, Volts, and current.
  • Ability to set minimum and maximum alarm trigger levels for current in amps for each phase.
  • Capability to integrate with building management systems (BMS), with ability to transmit data over an RS-485 link, wired Ethernet 10/100 link, or over a wireless mesh network.
  • Factory-built into Starline power feeds and plug-ins, providing a clean and seamless integration of monitoring with power distribution.
  • Optional display with touch screen interface.
  • <1% Accuracy

Monitoring solutions used in busbar systems provide seamless data from a brief overview down to the individual outlet level. Power usage data can be accessed locally or remotely allowing you to make purposeful energy efficient decisions.

Power monitoring helps to identify load imbalance before it impacts your equipment’s performance. Continuous monitoring allows you to capture changes due to new equipment and address a potential problem before downtime occurs. Being aware of power usage enables your company to scale with precision.

Busbar resources for download

Use this link to find whitepapers, product guides and tech briefs to continue your education of busbars.