MCBs are designed to be highly durable and withstand high current levels, making them ideal for both residential and industrial protection purposes. The technology is also more compatible with sustainable, next-generation electric energy solutions, including smart grids, electric cars and connected homes, which require even better downstream protection. Thermoset materials traditionally used to manufacture circuit breakers lack the design flexibility needed to produce complex housings for MCBs. Increasingly, breaker manufacturers are replacing thermosets with high-flow thermoplastics to improve the level of integration and functionality in MCB housings and produce them more cost-effectively. In addition to offering high heat resistance and dimensional stability, thermoplastics are also easier to recycle. Yet, MCBs must demonstrate best-in-class safety performance to handle higher currents and extend electrical endurance. Manufacturers must ensure thermoplastic parts meet all safety standards before approving them for production.

Working directly with industry-leading circuit breaker manufacturers, our team developed a complete thermoset replacement solution for MCBs. Our portfolio of Akulon®, Stanyl®, ForTii®, Arnite® and Xytron™ grades demonstrate unmatched performance in Comparative Tracking Index (CTI), Glow Wire Flammability Index (GWFI) and Underwriters Laboratories (UL) 94 flammability testing. Superior flow and processability maximize design flexibility for small and thin-walled parts, while low corrosion, high heat deflection temperatures (HDT) and excellent dielectric aging characteristics ensure high reliability throughout the lifetime of the end product. 

Our portfolio is designed to address the safety and performance requirements of individual MCB housing and internal parts. Enclosure thermoplastics provide a high CTI and flammability ratings, as well as excellent short circuit performance. Inside MCBs, materials for bobbin supports, which initiate short circuits, offer a high HDT and superior tensile strength, while flange materials ensure reliable arc-breaking. Solutions for switching mechanisms, which shut off power when dangerous conditions are detected, deliver low friction, low creep and high dimensional stability. DSM also offers numerous halogen-free, flame-retardant grades that improve final product sustainability. 

MCB arc-breaking mechanisms need to handle higher breaking capacities in a confined space to minimize risks of electrical accidents. Our thermoplastic solutions enable faster arc quenching that lowers energy dissipation, and demonstrate low soot formation that improves isolation resistance after multiple short circuits. This increases the long-term reliability of the MCB. Materials offer a melting point up to 295°C, ensuring part reliability in high voltage environments. Competing solutions, including bulk moulding compounds (BMC), polyamide (PA6)/polyoxymethylene (POM) and PA6/polypropylene (PP) blends melt in this environment.

At DSM, we know there’s no room for compromise when it comes to safety. That’s why our teams collaborate with leading power distribution experts to develop thermoplastic solutions you can depend on for developing reliable, high-performance MCBs that eliminate safety risks. Our global manufacturing, research and technology and application development teams continuously optimize and re-test our materials to meet your evolving requirements, enabling you to better lead your industry.

To learn more about DSM’s power distribution solutions, download our Material Safety and Performance for MCBs white paper. You can also visit plastics finder or contact us for more information.