Three Things to Consider When Selecting a Company Switch
Company switch is a term that originated from the stage and theatre industry for a distribution panel consisting of a circuit breaker or fusible switch, mounted in an enclosure feeding Camlock connections. The switch is usually mounted somewhere near the stage and is used to turn on and off power to the lights and sound of the stage. Although this is the most common and the original use, company switches are used in a variety of other applications where a disconnect and Camlock connections are used for temporary power. ATI Electrical Supply recently provided over 100 company switches for a convention center expansion in Las Vegas, Nevada.
Company switches come in a wide variety of sizes defined by voltage ranges including 120/240V single phase, 120/208V three-phase, 480V three-phase, and 480/277V three-phase. Amperages typically range from 60A to 400A.
When choosing a company switch manufacturer, customers should consider the three main components that make up the switch; the disconnect, enclosure, and Camlock connections.
The disconnect can be either a circuit breaker, a molded case switch, or a fusible switch. There are advantages to each, and the choice largely depends on the application. Circuit breakers are the most common disconnect means because they provide both thermal and magnetic protection of the cables and the load. They also provide a means of shutting off the power by opening the breaker through the use of an external handle. Molded case switches offer no thermal or magnetic protection, and are used when there is circuit protection somewhere ahead of the company switch. Fusible switches offer a higher degree of short circuit protection as well as thermal protection but need to be replaced once an overcurrent or short circuit event occurs.
Because company switches are used in both indoor and outdoor applications, the enclosure should have a NEMA 3R or NEMA 12 rating. NEMA 12 enclosures provide a level of protection against dust as well as falling water, therefore we recommend always using a NEMA 12 enclosure. Company switches are usually mounted in a visible location, therefore the aesthetics of the enclosure are also important. Power Assemblies uses enclosures coated with ArmorTEKtm which is a black coating similar to the material used on the bedliners of trucks, giving the enclosure an industrial yet professional look. Another consideration when choosing the enclosure is the layout of the interior, particularly the access to the Camlocks. Since cables are usually hanging down from the enclosure, there should be some strain relief provided through the use of slots to keep the cable from pulling too much on the connectors.
Although Camlocks, specifically 16 series 400A camlocks, are made to be interchangeable, there are some application considerations. One of the most important aspects is the color-coding of the camlocks, which should reflect the standard colors related to the voltage. For example, 120/208V configurations have black, red, blue, white and green cams, while 480/277V configurations have brown, orange, yellow, white, and green cams. These color code schemes help the electrician or portable power service technician to quickly identify the voltage of the company switch. As far as manufacturing brands go, any of the major brands will suffice since they are all electrically and mechanically compatible. Because the switches can go for extended periods of time without use, we recommend using a cap and lanyard to cover the opening of the camlock to keep out dust and moisture.
If you have a project or application containing a company switch, contact one of our knowledgeable sales people or product engineers at firstname.lastname@example.org and we’ll be glad to help.