Electrical switchgear refers to a centralized collection of circuit breakers, fuses and switches (circuit protection devices) that function to protect, control and isolate electrical equipment. The circuit protection devices are mounted in metal structures. A collection of one or more of these structures is called a switchgear line-up or assembly.
Switchgear is commonly found throughout electric utility transmission and distribution systems as well as in medium to large sized commercial or industrial facilities. Standards for electrical switchgear are defined by IEEE in North America and by IEC in Europe and other parts of the world.
Low-voltage metal-enclosed switchgear is a three-phase power distribution product designed to safely, efficiently and reliably supply electric power at voltages up to 1,000 volts and current up to 6,000 amps. Typical ANSI/NEMA (American National Standards Institute, National Electrical Manufacturers Association) switchgear is rated for up to 635 volts with a continuous current main bus rating of up to 10,000 amps (for supplying power from parallel sources).
Low-voltage switchgear is often found on the secondary (low-voltage) side of a power distribution transformer. This transformer and switchgear combination is known as a substation. Low-voltage switchgear is typically used to feed low-voltage motor control centers (LV-MCC), low-voltage switchboards and other branch and feeder circuits. It is used to supply electricity for critical power and critical process applications such as those found in heavy industry, manufacturing, mining and metals, petrochemical, pulp and paper, utility, water treatment as well as datacenter and healthcare.