Electrical installations usually have several loads, often on a single circuit. Panelboards, switchboards, switchgear and motor-control centers are methods of consolidating control of those circuits into a common enclosure on common bus. One of the basic functions of switchgear is protection, which is interruption of short-circuit and overload fault currents while maintaining service to unaffected circuits. Switchgear also provides isolation of circuits from power supplies. In addition, switchgear is used to enhance system availability by allowing more than one source to feed a load
Main Components of Switchgear
Common Types of SwitchgearSwitchgear is a broad term that covers electrical distribution systems made up of metal-clad or metal-enclosed cabinets containing switches or circuit breakers. The switches might be fused or non-fused. They might be air break or vacuum break. While manual break devices are the most common, medium-voltage switchgear could be electrically closed and or opened. Circuit breakers may be air break, oil break or vacuum break, even SF6. These will always be electrically closed and opened. Where the breakers or switches are electrically closed, opened or both, there will be a requirement for control power source and control power wiring. The source might be a remote separate source of low voltage brought in from outside the switchgear, or it might be provided by transforming line power down to the necessary control voltages. This standard covers the cabinets, busing, relaying and control circuits only.
ROMAC's Reconditioned Switchgear, Switchboard and PanelboardReconditioning is the process of returning electrical equipment to safe and reliable operating condition based upon the design of the original manufacturer at the time of manufacturing. ROMAC regularly carries all major manfuacturers of switchgear, switchboards and panelboards, including: GE, Cutler-Hammer, SquareD, Westinghouse, Siemens, and ABB. ROMAC follows PEARL industry standards to recondition switchgear, switchboards and panelboards. Following a visual inspection and disassembly, ROMAC technicians perform “as found” testing steps, which include but are not limited to insulation resistance, contact resistance and control device operations. The standard instructs the technician to evaluate the overall condition of the various means of isolating current carrying from non-current carrying areas of the system; proper level of conductivity through both main power and control power current carrying paths; proper operation of control devices and smoothness of operation of mechanical elements such as pivots, bearings, levers and springs; and debris, corrosion or indications of deterioration. Once all tests and inspections are preformed, the technician records the results on the standard’s Recondition Evaluation form. The visual inspection, along with the as-found testing, helps determine the actual recondition procedure. The reconditioning procedure specifies disassembly and cleaning of all parts and subassemblies, replacement of parts where necessary and tightening or adjusting where necessary. Assembly of the reconditioned components and subassemblies is followed by final inspection and testing. As with all testing, inspection, and reconditioning operations, final inspection and test results are recorded onto the Evaluation and Test forms included with the standard.