Miniature Circuit Breakers (MCB) are such devices that protect their connected circuits against short circuit and overload. In adition to this they fullfil closing and tripping functions as well. Sigma MCBs are produced as 3kA, 4.5kA, 6kA, 10kA and 16kA according to IEC/EN 60898-1 and comply with Europian Union Low Voltage directives 72/23/CE.