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Getting you on the right track


In this article the experts at Starline highlight the importance (and benefits) of evaluating flexibility in your track busway system and that not all systems are created equal.

For data centre owners and Consulting and Specification Engineers (CSEs), busway systems are rapidly becoming the solution of choice for effective power distribution.

Track busways can be suspended from the ceiling, placed on vertical supports, or even mounted on the server cabinets themselves to provide a direct power source to servers and racks.

Busway systems offer numerous advantages over traditional Remote Power Panels (RPPs). Suspended or mounted track busways eliminate the need for an RPP, allowing you to make better use of data centre space.

Busways also eliminate the need to run power cables and whips under plenums in a raised floor, allowing cooling air from below to flow unobstructed to the servers. If in-row cooling units are used along with busways, it eliminates the need for the raised floor itself.

A busway system gives you full visibility over your power distribution system, making it easier to do maintenance and troubleshooting. Unlike RPPs, electricians don’t have to shut down the entire system, or do hazardous work on a live and exposed panel, in order 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, you can easily and safely swap out old circuits and replace them with new ones in a matter of minutes.

But not all busway solutions are the same; some busway systems work better, last longer, and require less maintenance than others. When evaluating a busway system, it is important to consider the system flexibility.

An effective busway system gives you flexible design and power distribution options, allowing you to build out, scale up, and adapt your IT loads according to your changing power and facility needs.

Importance of flexibility

Power requirements in data centres are in a constant state of flux, as IT infrastructure is continuously deployed, scaled up, or reorganised according to the company’s needs.

Also, many large data centres are now upgrading their power systems at the rack level, from single-phase to higher-voltage (i.e., 400v or even higher) three-phase power. Facility owners need power distribution systems that can meet the ever-changing, ever-increasing power demands of their IT footprints.

You need a busway system that is easy to install and provides the flexibility of a customisable design to meet the layout of IT infrastructure within your facility.

You also need a busway system that is adaptable to different power levels, allowing you to scale up as the power needs of your IT deployments change. And you need a busway solution that allows for easy maintenance and replacement of parts.

Track busways

If a busway system is the ‘elevated highway’ that allows electrical power to travel from the PDU to servers and racks, then individual track busway sections are the ‘straights and curves’ that make up that ‘highway.’

There are typically the four types of busway sections:

  • Straight Busways (a): The main busway sections that deliver power to the IT infrastructure.
  • Elbow Sections (b): Used to make a horizontal, 90-degree turn in a busway run, by joining two straight sections.
  • Tee Sections (c): Used to create a 90-degree branch leg, by connecting three different straight sections.
  • Power Feed Units (d): A unit that supplies incoming power from the PDU to the busway. A power feed unit may also include power monitoring equipment, a serial, Ethernet, or Wi-Fi connection for reporting data, and an Infra-Red (IR) window for thermal scanning.

In a data centre, existing infrastructure is often space constrained. A track busway system should offer flexibility of design, allowing you to create system layouts that help you to make full use of your IT deployments.

The busway system should utilise 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, utilising tees and elbows can reduce the number of end feed connection points that you require.

Additionally, you should look for a solution that offers busways with wide range of amperage options, with plug-in units being interchangeable between the range.

A good range for continuous track busways is from 40 to 1,200 amps. This will enable you to scale up your power delivery options easily as your power needs change over time.


A joint provides a connection between adjacent busway sections, or between a straight busway and an elbow or tee section. Different busway providers use different types of joints. But you should look for vendors that utilise the most reliable kind of joint – a compression-fit joint.

A compression-style joint kit consists of (a) a bus connector – that is, copper blade busbars secured to an insulating mounting plate – and (b) a pair of housing couplers. The joint should be easy to install but should have elements (i.e., plastic blockers in the housing couplers) that prevent it from being installed incorrectly. 

The busbar blades on the bus connector provide the electrical connection between busbars in the two adjoining sections. The two housing couplers are then used to connect the aluminum housing of the two sections at the top and bottom of the joint.

With this kind of joint, the mechanical connection is entirely separate from the electrical connection. Even if the screws that secure the couplers become loose, the electrical connection between busbars will remain intact.

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

Plug-in units

The plug-in units (a.k.a. tap boxes) distribute the branch circuit power load from the busways to the servers, racks, or other equipment. Plug-in units can be easily added or removed to the busway units as needed.

A busway solution should offer a wide range of plug-in units to handle different power demands and topologies.

For example, if you decide to upgrade your power distribution at the rack level from single phase to three-phase power, you should be able to easily upgrade your busway system by buying new plug-in units to handle the increased power requirements.

Additionally, plug-in units should be compatible for use with busways of different power levels (i.e., 250, 400, 1,200 amps).

Power monitoring

Today, many data centre owners do power monitoring at the PDU and rack PDU level. But this is not enough.

For a more complete package of data, and to ensure the reliability and safety of your entire power distribution system, you should look for a busway solution that allows you to do power monitoring at various points along your busway runs.

A power monitoring system should have the ability to monitor up to six single-phase branch circuits or two three-phase branch circuits from the same meter. The plug-in units and end feed units should enable you to monitor and report power use at the rack PDU level, and over the entire busway run.

Also, a 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.

Additionally, it should offer an embedded web page for access to system configuration or data, or easy integration with your Building Management System (BMS) or Data Centre Infrastructure Management (DCIM) system.


For data centre owners, CSEs, and others who are seeking power delivery solutions, the ultimate goal in selecting a busway system should be peace of mind. You want the certainty and confidence that your power distribution system will always be able to deliver the power you need to your servers, racks, or equipment.

A busway system is not just a power solution. It provides a competitive advantage, allowing your data center to stay operational, and delivers flexibility to adapt to the layout and changing power needs of your facility.

Contact Starline  | [email protected] | +44 1183 043180

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