Energy, Power

How to spot the top three track busway qualities

What to look for in a track busway power distribution system

By Doug Moore August 18, 2021
Courtesy: Starline

Overhead power distribution by means of track busway systems is rapidly becoming the solution of choice in data centers, industrial and manufacturing plants and other facilities that require continuous uptime and faster adaptability. With a track busway system, power is supplied by forming a custom electrical grid above the production floor (see Figure 1). Plug-in units can be inserted at any location along the busway channel to provide the required power at the point of use where the electrical load needs it.

Track busway systems offer numerous advantages over traditional power systems. Suspended or mounted track busways eliminate the need for a remote power panel (RPP) in data centers or pipe and wire electrical distribution in other facilities, providing flexibility and scalability for electrical reconfiguration.

A busway system provides visibility over the power distribution system, making it easier to do maintenance and troubleshooting. Unlike traditional power systems, electricians don’t have to shut down the entire system to change out a single circuit breaker. Using plug-in units (a.k.a. tap-off boxes), which are inserted into the busway’s open channel and connected to the internal busbars, users can safely swap out old circuits and replace them with new ones quickly.

Four elements make up a busway system: track busways, joints, plug-in units and power monitoring. But not all busway solutions are the same; some busway systems work better, last longer and require less maintenance than others. In evaluating a busway solution, look for the following qualities and how they apply to each of these elements:

  • Reliability: An effective busway system provides reliable and efficient power distribution, a maintenance-free joint design and a long useful life to ensure continuous uptime for critical equipment.
  • Flexibility: An effective busway system provides flexible design and power distribution options, allowing users to build out, scale up and adapt production equipment according to changing power and facility needs.
  • Safety: The elements of a busway system should guarantee safety for workers, equipment and the facility.

Reliability

Track busways. When evaluating a busway system, look for several features in the track busway sections that contribute to reliability. Each section should be made of high-grade engineered materials with a lightweight aluminum housing and either 99% pure copper or copper-contact aluminum hybrid (for higher-power delivery) roll-formed busbars. The bottom should be an open, continuous access slot that runs the length of the busway section, allowing use of the total available space to insert plug-in units.

The best design is a U-shaped busbar, which provides a continuous receptacle fitting for two types of connections: (1) a compression-fit joint to link busway sections together, and (2) a compression-fit electrical connection for the plug-in units in the busbar.

Finally, look for a busway that offers longer track busway sections, i.e., 3 to 6 meters (10 to 20 feet) in length. Since joints often are the main failure point in traditional busbar systems, having longer busway sections reduces the number of joints. Also, longer busway sections enable users to hang more plug-in units in a single busway section.

Joints. A compression-fit joint is the most reliable type of busway joint available. Failures of this joint type are virtually unknown. The compression-fit joint is 100% maintenance free. Once it has been installed, no maintenance is required to preserve the joints between busway sections.

When the joint is installed, the “knife blade” compression fit forms a solid electrical connection between busbars, and “wipes away” any oxidation that might interfere with electrical conductivity, producing a 100% reliable connection every time. Unlike other busway joints, a compression joint does not require copper grease to improve busbar conductivity or prevent oxidation.

Plug-in-units. A plug-in unit should have a robust design with minimal moving parts and the fewest electrical connections possible to deliver power to the critical load. The fewer moving parts, the more reliable it will be.

Also, a plug-in unit should have a simple paddle assembly as its electrical connection. When one inserts this paddle into the busway, and turns it, the paddle’s terminal stabs form a reliable compression-fit joint connection with the busbars. The plug-in unit should not rely on accessory mechanisms with springs and clips to make its electrical connection.

Power monitoring. Look for a busway system that monitors and tracks power and temperature data over time. It should have revenue-grade metering to ensure readings will be accurate and correct. This type of monitoring allows users to verify busway runs are working properly, joints are intact and equipment is operating at optimum power levels.

Flexibility

Track busways. A track busway system should offer flexibility of design, allowing users to create system layouts that help make full use of equipment.

The busway system should use not just straight busway sections of different lengths, but also elbow and tee sections. (Not every busway solution has these.) Also, the system should offer flexible options for where to place power feed units, including “end feed” units, which are installed on the end of the busway run, and “above feed” units, which are installed along the topside of the busway. In some cases, using tees and elbows can reduce the number of end feed connection points required.

Look for a solution that offers busways with a wide range of amperage options, with plug-in units being interchangeable between ranges. A good range for continuous track busways is from 40 to 1,200 amps. This will enable scalability of power delivery options as power needs change over time.

Joints. Joints are an essential element in flexibility of busway design, allowing users to link together track busway sections to form a busway run. It is important to have a strong joint that works in tandem with the other elements to form a durable and dependable busway system.

Plug-in-units. A busway solution should offer a wide range of plug-in units to handle different power demands and topologies. Plug-in units should be customizable to unique power requirements and should support the integration of multiple electrical components into a single unit such as circuit breakers, meters, duplex/quad receptacles, cords, etc.

Power monitoring. A critical power monitoring system should offer flexible data reporting options through wireless Ethernet (802.11), wired Ethernet and/or serial communications. It should be able to simultaneously use all reporting protocols. It should offer an embedded web page for access to system configuration or data, or easy integration with a building management system (BMS) or data center infrastructure management (DCIM) system.

Figure 1: With a track busway system, power is supplied by forming a custom electrical grid abovethe production floor. Courtesy: Starline

Figure 1: With a track busway system, power is supplied by forming a custom electrical grid above the production floor. Courtesy: Starline

Safety

Track busways. Look for a busway system that includes multiple provisions to deal with potential arc flash scenarios. The solution should have the following:

  • Certifications from nationally recognized test labs
  • Selective coordination of fuses, which, in the event of a power surge, allows the busway system to lower potential incident energy to negligible levels
  • Arc flash certifications that include operator and equipment safety
  • Short circuit ratings
  • An ingress protection (IP) safety rating of at least IP2X (“finger safe”) and, if possible, options for IP3X (“tool safe”).

Also, look for a busway system that provides multiple ground path options:

  • Standard (protective) ground system: The busway’s aluminum housing provides the system’s ground conduction.
  • Isolated ground system: The ground conductor and the housing ground are isolated from each other in all components.
  • Dedicated ground system: The ground conductor and housing ground are bonded together at the end power feed.

Joints. The housing couplers in the joints carry ground conduction through the aluminum housing from busway section to section. It is important to find a busway solution with reliable, well-designed joints to maintain the ground conduction system.

Plug-in-units. Safety of plug-in units is a primary concern, especially for facility engineers who often need to install tap boxes on live busways. At the most basic level, every plug-in unit from any vendor will have a grounding tab or device, which automatically grounds the unit prior to the electrical connection of the conductors into the busbars. However, look for a busway solution with additional safety features.

First, the design of the busway itself contributes to safety where plug-in units are concerned. An asymmetrical U-shaped busbar design makes it impossible to install a plug-in unit incorrectly. This, in turn, makes it impossible to cross live phases or ground paths when installing the plug-in unit into a live busway.

Also, look for a busway solution where the plug-in units come with optional safety accessories. These might include:

  • “Floor operable” electrical connections
  • Breaker interlocks
  • Finger shrouds
  • Infrared (IR) windows.

Power monitoring. A power monitoring system should have the ability to send out preset alarms in the event of a failure or emergency. For example, if a busway end feed rises to within 10 degrees of an unsafe temperature (i.e., around 85°C), the power monitoring system should have the ability to send an automatic email alert, or to provide that data to a BMS or DCIM, to warn that a cable installation is potentially overheating and may cause a fire.

The monitoring system also should offer breaker-position sensing, which allows users to monitor whether plug-in units are operating correctly. Again, the system should allow users to preset alarms, so if, for example, a plug-in unit suddenly shuts off, users will receive an automatic email alert, indicating equipment may have overheated and triggered the breaker.

What to look for in a busway provider

In choosing a track busway system, evaluate the provider using the following criteria:

Experience. A busway provider should have years (preferably decades) of experience in busway design and manufacturing. The provider should be able to demonstrate longevity of product, that is, they should have a record of installing busway systems still operational after years of use by their customers.

Also, the provider should have a list of clients from a variety of different industries such as data center and colocation providers, Fortune 500 companies, government organizations, industrial and manufacturing facilities, banks and investment firms, universities and hospitals.

Quality ratings (metrics). A busway provider should have a series of quality ratings. If the provider can’t give you the following ratings for its company, you may want to look elsewhere.

  • Six Sigma. The company should be able to provide its Six Sigma quality rating.
  • Shipments versus return material authorization (RMA). The provider should have a high number of overall busway shipments versus an extremely low number of returns due to product failure.
  • Mean time between failure (MTBF). The busway provider’s products should have a long average time between failures. The higher the MTBF, the more reliable the product is.

Custom-designed busway solutions. A busway provider should offer a range of highly configurable products and services. It should be able to help identify busway designs that will fit the layout and needs of a specific facility. For example, it should be able to provide color-coordination of busway, which can help to reduce or eliminate downtime due to human error.

Also, a busway provider should be able to engineer and manufacture customized products on demand according to specialized needs. Engineers should be available worldwide to help design custom plug-in or end feed enclosures and busway systems that meet specific electrical ratings or size requirements. The provider also should have a production lead time that fits the schedule and should be able to complete orders in accordance with deadlines.

Post-sales technical and onsite support.

A busway services company should provide the following:

  • A global network of experienced sales representatives who can answer easy questions about its busway products
  • A global services team of factory-certified technicians who can help with onsite installation, commissioning, troubleshooting and routine maintenance
  • A global engineering team ready to support specific projects
  • 24/7 availability of technical support.

Conclusion

The goal in selecting a busway system should be peace of mind. Users want the certainty and confidence that their power distribution system will always be able to deliver the power they need to their equipment.

A reliable busway system is not just a power solution. It provides a competitive advantage, allowing facilities to stay operational. This ensures companies will always be productive and able to deliver products or services to their customers. It is essential to select a busway system that will guarantee the safety of workers, with the flexibility to adapt to the layout and changing power needs of the facility. If users evaluate the elements of a busway system based on reliability, flexibility and safety, and look for an experienced and highly-qualified provider who can also be a reliable business partner, they can choose a busway solution that will effectively serve their power distribution needs over the long run.


Doug Moore
Author Bio: Doug Moore is Industrial Product Manager at Starline, a brand of Legrand.