Series of multi-pole circuit breakers having different sizes and rated current capacities, the individual sizes (1; 2; 3) each - having a switch latch (24; 25) for closing and opening main contacts, - having thermal and magnetic trips (48; 50) which are operatively connected to the switch latch such that they can be tripped, in order to cause the main contacts to open in the event of overcurrents or short-circuit currents, - having a U/A trip, if necessary, which is operatively connected to the switch latch such that it can be tripped, in order to prevent the main contacts from closing or to allow the main contacts to open in the event of undervoltage or an operating current in the U/A trip, for which purpose the U/A trip is released by means of a first release element connected to the switch latch before the main contacts close, in a switch housing (4; 5; 6), a U/A trip of the same type being provided for every series size (1; 2; 3), characterised in that - from the series, at least one size having a relatively high rated current capacity is equipped with an energy accumulator which consists of a ratchet lever, a tripping lever and a tension spring, pressure being applied to the tripping lever by the ratchet lever of the switch latch as it returns from the tripped state, counter to the action of force of the tension spring, in order to bring about the tensioned state, - in that, in the case of the at least one size equipped with an energy accumulator, on the one hand the thermal trip, the magnetic trip and the U/A trip are brought into operative connection with the ratchet lever in order to relax the energy accumulator and, on the other hand, the tripping lever is brought into operative connection with the switch latch, such that it can be tripped, as a result of the action of the self-relaxing tension spring, - in that, in the case of the at least one size equipped with an energy accumulator, instead of the first release element which is effective in the case of the other sizes (1; 2), a second release element which is connected to the switch latch of the first release element is provided in order to enable the U/A trip, the release position of the second release element which is effective before the main contacts close being largely in advance of the release position of the first release element. - having a switch latch (24; 25) for closing and opening main contacts, - having thermal and magnetic trips (48; 50) which are operatively connected to the switch latch such that they can be tripped, in order to cause the main contacts to open in the event of overcurrents or short-circuit currents, - having a U/A trip, if necessary, which is operatively connected to the switch latch such that it can be tripped, in order to prevent the main contacts from closing or to allow the main contacts to open in the event of undervoltage or an operating current in the U/A trip, for which purpose the U/A trip is released by means of a first release element connected to the switch latch before the main contacts close, in a switch housing (4; 5; 6), a U/A trip of the same type being provided for every series size (1; 2; 3), characterised in that - from the series, at least one size having a relatively high rated current capacity is equipped with an energy accumulator which consists of a ratchet lever, a tripping lever and a tension spring, pressure being applied to the tripping lever by the ratchet lever of the switch latch as it returns from the tripped state, counter to the action of force of the tension spring, in order to bring about the tensioned state, - in that, in the case of the at least one size equipped with an energy accumulator, on the one hand the thermal trip, the magnetic trip and the U/A trip are brought into operative connection with the ratchet lever in order to relax the energy accumulator and, on the other hand, the tripping lever is brought into operative connection with the switch latch, such that it can be tripped, as a result of the action of the self-relaxing tension spring, - in that, in the case of the at least one size equipped with an energy accumulator, instead of the first release element which is effective in the case of the other sizes (1; 2), a second release element which is connected to the switch latch of the first release element is provided in order to enable the U/A trip, the release position of the second release element which is effective before the main contacts close being largely in advance of the release position of the first release element.