The NB8-40J Miniature Circuit Breaker (MCB) offers robust overload and short-circuit protection for electrical circuits up to 40A. Designed for AC 230/400V, 50Hz systems, it features versatile B, C, and D tripping curves to suit diverse load characteristics, from protecting personnel and cables to managing high inrush currents. This essential device ensures circuit safety and isolation, making it an ideal choice for residential, commercial, and industrial electrical distribution systems.