A terminal box (45) for electrical connection to an electric motor (32), in particular of a circulation pump (10), includes at least one wall (215) and at least one circuit board (145), wherein the terminal box (45) on the wall (215) includes at least one electrical contact (220) for connection to the circuit board (145), said contact designed as a clamping element (220) for releasably clamping the circuit board (145) which is orientated with its flat sides (150, 152) perpendicularly to this wall (215). A terminal box system includes at least two different circuit boards (145, 145′) selectively insertable into the at least one clamping element (220) of the terminal box (45) and/or at least two different covers (105, 105′) selectively connectable to a housing part (100) of the terminal box (45). A pump assembly (5) includes such a terminal box (45) or such a terminal box system.