Article
As an industrial electrician, I've installed miles of conduit. And of 
course, once installed, even more miles of cables and conductors had to 
be snaked through it.<br><br>Even with raceways, it's always at least a two-step process – raceway, then conductors. <br><br>Of course, that will always be a part of many installations.

Busways – An Alternative to Conduit and Cable

Steve Maurer, IME
As an industrial electrician, I've installed miles of conduit. And of course, once installed, even more miles of cables and conductors had to be snaked through it.

Even with raceways, it's always at least a two-step process – raceway, then conductors.

Of course, that will always be a part of many installations.

But, what about an alternative that can save time and money during major power installs?

And what if power distribution could be shortened, in many cases, to a one-step procedure?

Sounds like a plan to me.

Enter … the busway.

What is a busway, anyway?

The National Electrical Manufacturers Association (NEMA) defines it as: "a prefabricated electrical distribution system consisting of bus bars in a protective enclosure, including straight lengths, fittings, devices and accessories."

Just like conduit and cables, it moves electricity from one location to another. It can be used to connect switchgear, panelboards, and transformers.

Without the wire-pulling hassle, I might add.

Basic Busway Components

The basic structure of a busway consists of:

  • Bus bars – the conductors that carry electricity from point A to point B. Could be made of either aluminum or copper, and sized to fit the anticipated load.

  • Housing – the outer protective structure (think raceway or conduit) that contains the bus bars. Usually made of aluminum or steel.

  • Insulating system – wires and cables use an outer covering or set of coverings to insulate the wires. Busway uses a combo of air, epoxy and mylar. Air gaps help prevent arc jumps.

  • Fittings – elbows, offsets, and tees are the major fittings. These are pre-made, so no conduit bending needed. I like that, personally.

There are some other optional components that we'll discuss in another article.

Several Busway Flavors … But No Chocolate or Strawberry

Busway comes in several "flavors" or styles as well. Each type is suitable for particular voltages, loads, configurations, and market segments.

  • Non-segmented busway is often used for applications up to 38kV and 6000 A. Heavy duty stuff for use in electrical utilities, petrochemical sites, and heavy industry.

  • Sandwich-style busway is used in applications up to 600 V and 5000 A. Market segments include commercial construction, general and heavy industry, and data centers.

  • Track busway is a lighter duty busway, often used where occasional reconfiguration is necessary. Rated only for indoor use, it's often used in data centers, laboratories, and warehousing. Available for voltages up to 600 V and up to 225 amps. It often has either fixed receptacles or cord drops attached.

  • Air-insulated busway is common in data centers, machine shops, and laboratories. Rated for indoor use only, it's available for up to 600 volts and 600 amps. The enclosure is made of aluminum, so it's lightweight. It's best for medium ampacities at low voltages.

In another article, we'll take a more in-depth look at busways, a great alternative to conduit and raceways
Photo courtesy of Eaton
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