Commercial and industrial distribution systems use various methods to conduct electric power. These methods often include heavy conductors that work in trays or ducts. The cable and conduit assemblies are expensive and their installation requires a lot of time. Once installed, they are difficult to change. To eliminate these deficiencies, energy is often distributed using closed bus bars. This is known as a busway.
A bus bar is a conductor that serves as a common connection for two or more circuits. It is represented schematically by a straight line with a number of connections made to it. Busway bus bars are made of aluminum or copper.
Busways are defined by the National Electrical Manufacturers Association (NEMA) as a prefabricated electrical distribution system consisting of bus bars in a protective enclosure, including straight lengths, fittings, devices, and accessories. Busways includes bus bars, an insulating and/or support material, and a housing.
A major advantage is the ease with which busway sections are connected. Electrical power can be supplied to any area of a building by connecting standard lengths of busways. It typically takes up to 35% fewer man-hours to install or change a busway system than cable and conduit assemblies.
Busway is used in a wide variety of applications, including complex industrial plants, data centers, offices, high-rise
buildings and many other types of facilities. Generally, there are two major types of busway installations: horizontal
and vertical. Horizontal busway is often used in industrial locations to supply power to heavy equipment, lighting, and air conditioning. Vertical busway, also referred to as busway risers, can be installed economically in high-rise buildings where it is used to distribute lighting and air conditioning loads.
Siemens Sentron busway is used to explain and illustrate basic principles and features. Sentron busway is available with continuous current ratings from 225 to 5000 amperes and meets the requirements of most applications.
Types of bus ways
- BD Busway has set the industry standard for more than 70 years.
- XJ-L Busway is an excellent choice for high-tech or light industrial applications.
- XL-U Busway is designed for voltage-sensitive, heavy-duty applications, such as welding.
There are two types of busways: feeder and plug-in.
Many industrial and large commercial applications have long runs from the power source to a single load or to a panel board, switchboard, or motor control center lineup for further distribution. Feeder busways are intended for these applications or other applications that do not require power drops over the length of a bus way run.
Plug-in busways are used when power requirements are distributed over a large area. Using plug-in units, load connections can be added or relocated easily. It is designed for indoor use only