A busway is a grounded metal enclosure that contains factory-mounted bare or insulated conductors, which becomes an effective medium to distribute power. If you need to add a load or extend the power of an existing distributing system, you need a bus way.
An electrical bus way was first introduced in 1932 when the automotive industry needed a flexible power distribution system to serve its linear layouts. The bus way met that need and has since become an important device serving different purposes.
Today, GE is the leading manufacturer of the bus way. Its products are known for their strength and higher bearing rate compared to cables. Because they are made of stainless steel, they do not melt when high current passes through them. Sheathed insulation and cable melt under high currents.
The specifications of a busway depend on the requirements of the industries. The variations include high short-circuit interrupting ratings or AIC, multiple-ground designations and 200% neutrals. In contrast to most people’s presumption, this kind of power-distribution system can serve both for low and high amperage applications.
There are many ways to use this system. You can mount it in applications where you would normally use cable and conduit. The manufacturers of bus duct, its other term, create systems ranging from 100A to 6500A.
The low amperage applications include the high-technology firms like computer manufacturers and test laboratories. The high amperage applications include the automotive industry and heavy assembly industry. Because the needs vary, the manufacturers developed elbows and offsets to make directional alterations easy.
With this development, busway provides versatility in layout. And when there are new loads to develop, it is not difficult to meet the new conditions; you simply add tap-off units or new sections. But, you have to understand that a bus duct is not the best solution for all applications.
According to the National Electric Code or NEC section 364, paragraph 4b, you cannot install a bus duct when it is subject to severe physical damage or corrosive vapors. A bus way has several styles, but the most common is the sandwich style. It has a compact design and the ability to handle high short-circuit electric flow.
There are also other styles, which require you to use space bus bars. The insulated bus bars use materials like Mylar, epoxy or Polyvinylchloride. Many busway manufacturers produce this style using either copper or aluminum bus bars enclosed in aluminum or steel housing. The aluminum housing is lightweight and ideal as a ground path. Steel housing is also ideal for ground path but you need to check with the manufacturers.
Before you use a busway, you have to develop sketches of the route that the bus duct will follow. You have to indicate all bends, switchboards, floor elevation changes and columns. When you are done, you submit this plan to the manufacturer. He will develop the final layout drawings for approval.
Upon approval, the manufacturer constructs the bus way in sections and labels them in sequence. Few manufacturers offer a final connection program. You will mark the sections of the run as “X” at the time you place the order. You can then start the installation and order the final connection pieces, when you have determined the final dimensions.