Electronic trip unit for a low-voltage circuit breaker including a receptacle for a module, and a module for connection to the electronic trip unit

An electronic trip unit for a low-voltage circuit breaker for an electrical three-phase AC circuit, comprising:

• a housing including a front face, a rear face, a left-hand face, a right-hand face, a top face and bottom face;
• a controller, configured to
• compare supplied current measurement values of the electrical three-phase AC circuit with at least one of current limit values, current period limit values and time period limit values, and
• output a tripping signal, for interrupting the electrical three-phase AC circuit, upon the at least one of the current limit values, the current period limit values and the time period limit values being exceeded;
• and
• a receptacle for a module, configured to provide a force-fitting connection between the module and the electronic trip unit,
• wherein the module is receivable by the left-hand face, the right-hand face, the top face or the bottom face of the housing;
• wherein the front face of the housing includes a viewing window, at least a portion of the module, upon the module being received by the housing, being visible,
• wherein at least one function of the electronic trip unit is activated upon the module being received, and
• wherein the module is locked and is receivable or removable only in a zero-voltage state.