New ABB R-MAG outdoor vacuum circuit breaker housing gains NEMA 4 rating
12 June 2023
Since its launch in 2002, the R-MAG magnetic outdoor circuit breaker from ABB has been consistently tested in nearly 40,000 installations worldwide. Now, its new housing has been given the coveted 4 rating by the National Electrical Manufacturer Association (NEMA).
Natural disasters caused by extreme weather, including flooding, heat and drought continue to affect energy security and impact millions of people and businesses each year, costing billions. In response to these challenges and to meet customer demand for power safety and reliability, ABB has designed a next-generation extreme weather resistant housing cabinet for its R-MAG magnetically actuated dead tank breaker for medium-voltage primary substations.
Available for 15, 27 and 38kV units, the housing has been designed to the stringent NEMA 4 rating standards, offering unparalleled protection against even the most severe water and dust ingress. Featuring seamless roof-to-wall joints and external self-sealing bolts that prevent any gaps, the housing is completely secure and watertight. A new roof overhang also helps limit water exposure, plus the bushings-to-roof interface is secured by a superior aerospace-grade UV-resistant and more robust gasket.
These technological improvements on the traditional NEMA 3R housing make this R-MAG magnetic outdoor circuit breaker altogether safer and more reliable.
Additionally, ABB is releasing a new arc-resistant housing variant for the R-MAG breaker, tested as per IEEE C37.20.7, Type 2B, 0.5s. This new enclosure ensures any fire and gases are expulsed in a con-trolled manner in the event of an internal arc fault; there is increased protection for substation personnel on all sides of the equipment, much lower risk of failure and downtime, plus faster overall restoration of the system.
Ivan Contreras, ABB’s Global Product Manager for MV Dead Tank Breakers, said, “With the severity and regularity of both rain and dust-based storms challenging installations even further, we’ve used our magnetic actuation and vacuum interrupter domain expertise to create the best performing housing against intrusion of the elements with internationally-recognised NEMA 4 rating. Not only does this give our customers peace of mind in terms of safety, but also saves operational time and training and significantly reduces inspection and downtime costs.”
Even better for OEMs, a three-point latch and self-aligning hinges help to ensure a smooth and uniform door fit, while the enhanced position indicator window design also repels excess water levels. The foot-prints of the R-MAG 15 and 27kV units have even been reduced from 60 inch width down to 52 inch width, offering space and resource savings.
Based on magnetic actuation, the R-MAG breaker has fewer moving parts and is mechanically simpler than breakers with traditional spring mechanisms.
“The magnetic actuator is that rare maintenance-free mechanism, because only one moving part makes for minimal wear and tear. This is pretty unique, as spring-based alternatives with open compartments expose technicians to the danger of mechanical components, plus multiple gears and chains require a lot of regular cleaning/lubrication and spare parts - and are far less reliable when it comes to maintaining critical power supply,” concluded Contreras.
More information here.
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