In residential and small commercial applications, where the load on electrical circuits is typically small, power is distributed with insulated wiring and conduit. However, wire diameter must be increased as current rises, and there is a point where it ceases to be practical. In these cases, it is necessary to use bus bars for power distribution, which are typically manufactured from aluminum, copper or brass.
Unlike wiring, which runs inside conduit, bus bars require a specialized type of enclosure called a bussed gutter. The metal fabrication procedure used to manufacture these gutters must ensure that the final product accomplishes two important functions:
- Protecting the internal connections and bus bars from environmental factors such as dust and weather conditions.
- Providing complete electrical isolation from the surroundings, making sure bus bars do not represent a hazard for personnel.
Some examples of applications where bussed gutters are required include electrical switchyards, large commercial facilities and industrial manufacturing plants.
Advantages of Bussed Gutters in High-Current Applications
There are many performance and safety benefits of using bussed gutters for high current applications:
- A bus bar can dissipate heat more efficiently compared to an insulated wire of the same current-carrying capacity, thanks to its large surface area. This reduces the temperature of the electrical distribution system, increasing the service life of components and the overall energy efficiency of the installation.
- Electrical connections between wire segments become more difficult as conductor diameter increases, becoming impractical when multiple loads must be connected to the same conductor. A bus bar, on the other hand, offers the convenience of bolted or clamped connections; powering multiple devices with the same set of bus bars is very simple.
Recommendations When Purchasing Bussed Gutters
It is important to keep in mind that a bussed gutter holds electrical components carrying several hundred amperes, and safety is of paramount importance; it is necessary to have the right type of enclosure for the application. In addition, even if the enclosure is suitable, it must be a product whose safety has been validated by laboratory tests.
In the United States, the National Electrical Manufacturers Association (NEMA) is one of the main authorities on the manufacture and standardization of electrical products. NEMA has a classification for electrical enclosures based on the environmental conditions to which equipment is exposed, and selecting the right type is very important to guarantee optimal operating conditions and safety. Some of the factors to take into account when selecting the type of NEMA enclosure for a bussed gutter are:
- Location: Indoor or outdoor
- Degree of exposure to dust
- Degree of exposure to water
- Presence of corrosive agents or explosive compounds in the environment