Remote fault/smoke detection for motor control centres

Commercial smoke detectors have been included in the design and installation of switchgear rooms for years. It has been assumed that the use of pendent smoke detectors provided adequate monitoring for the detection of smoke and fire in switchgear rooms. However, reports indicate that smoke detectors are not always triggered even though smoke is evident. In fact, in some cases smoke from electrical equipment was billowing out from under the doors of the switchgear rooms and still no alarm was given. The research and testing of the use of smoke detectors installed directly inside low-voltage motor control centres is described. Also, the reasons why externally mounted devices, such as the ceiling, pendent, or low-elevation smoke detectors, are not adequate in detecting smoldering or burning electrical insulation are addressed. It is concluded that, by installing smoke detectors directly inside and at the bottom of electrical equipment such as motor control centers, improved monitoring for the early detection of insulation failures and fires can be achieved.<>