Panelboards and Switchgear

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.