The ABB 2P40A50A63A is a 2-pole, 40A, "A" characteristic Miniature Circuit Breaker (MCB) designed for final distribution circuits. This MCB provides reliable protection against overloads and short-circuits for electrical cables and equipment in residential, commercial, and light-industrial installations. The "A" tripping characteristic is a specialized curve that provides a very fast magnetic trip, designed specifically for protecting long cable runs, circuits with semiconductors, or highly sensitive equipment where even a moderate overcurrent must be interrupted extremely quickly to prevent damage or fire risk.