Modular overcurrent circuit breakers are universal devices for all types of applications meeting high standards for domestic use in the current rating range of 1 to 63 A. They can be combined with a wide range of accessories, including auxiliary contacts, auxiliary trip contacts, rise, undervoltage and overvoltage triggers or residual current blocks. Various combinations of accessories can be created. These combinations are limited only by the total number, not the type of accessories - all components fit together. Up to three units of auxiliary contacts or trip contacts and up to two units of triggers can be installed.