Panelboards and switchgear are electrical distribution devices that convert incoming electrical power into several smaller circuits and provide overload protection in the form of fuses or circuit breakers. Fuses contain a metallic element that melts when current exceeds specific amperage. Circuit breakers are mechanical switching devices that break currents under specified, abnormal circuit conditions. Some switches are manually controlled. Others are used with automatic standby generators that operate with single-phase or three-phase power and standard voltages during fail over. Supervisory control and data acquisition (SCADA) switches are used to control distributed systems from a master location. Panelboards and switchgear that contain circuit breakers use either thermal-magnetic or electronic trip units. To break the circuit, thermal-magnetic devices use either the current’s heating effect or the magnetism created when the current passes through a small coil. Electronic trip units provide adjustable trip characteristics such as configurable trip threshold and delays.

Variations

Panelboards and switchgear vary in terms of number of panels, mounting style, and electrical specifications. Single-panel and multi-panel devices are commonly available. Modular units bundle electrical distribution equipment into a single, factory-assembled, wired and integrated system in order to save space and reduce installation time. Factory-sealed devices are designed for use in hazardous areas with flammable gases and vapors or combustible dust. There are several mounting styles for panelboards and switchgear. Some devices mount on poles or racks. Others are ground-mounted or designed to be fully submerged in water. Electrical specifications for panelboards and switchgear include maximum voltage and maximum current. Single-phase devices distribute a single AC voltage. Three-phase devices deliver three AC voltages that are 120° out of phase with each other.

Applications

Panelboards and switchgear are used in a variety of applications and industries. For example, some devices are used to power lighting systems or motors with small electrical loads in commercial and industrial facilities. Others are designed for critical power distribution in uninterruptible power supply (UPS) and inverter applications, ensuring that one faulted circuit will not adversely affect the other branches. Customized panelboards and switchgear are available for both new construction and matching existing installations.