Assembly comprising a cable (100; 200; 300; 400), a connector (700; 750) that engages onto the cable, a box for electric wirings that carries the connector, a branching conductor connected to the connector, wherein the cable comprises an outer jacket (101; 201; 301; 401) and adjacent to each other a first, a second and a third conductor that extend within the outer jacket substantially parallel to each other and at substantially fixed mutual distances in a notional common straight plane, wherein the first, second and third conductor of the cable are each built up with an insulating sheath (12, 22, 32) of electrically insulating material in which a core (11, 21, 31) of electrically conductive material is accommodated, wherein the connector comprises a housing, electrical contacts that cut through the jacket and a branch connection (724, 725, 726, 754) for the branching conductor, wherein the electrical contacts each cut through the outer jacket and the insulating sheaths of the first, second or third conductor and then are in electrically conductive contact with its core, wherein the branch connection is electrically conductively connected to at least one of the electrical contacts, wherein the connector is provided with a cable carrier partially accommodated in the housing and the electrical contacts project from the housing in the direction of the cable carrier, wherein the cable carrier is movable with respect to the housing between a first pre-determined position in which the electrical contacts are spaced apart from the outer jacket, and a second pre-determined position in which the electrical contacts cut through the outer jacket and the insulating sheath, wherein the box is provided with a circumferential wall and a bottom wall (802a, 802b) that bound a cavity for electric connections to which the branching conductor leads, wherein the box furthermore comprises a connector holder for the connector, wherein with respect to the housing the connector holder is adapted and positioned for carrying the connector with the cable holder so as to face away from the box, characterized in that the assembly comprises a pair of pincers for connecting the connector to the cable, and wherein the first, second and third conductor of the cable are each built up with the insulating sheath (12, 22, 32) of electrically insulating material in which only one singular solid core (11, 21, 31) of electrically conductive material is accommodated, wherein the cable carrier at the side facing away from the housing is provided with a substantially straight first engagement surface for the pair of pincers and the connector (700; 750) at the opposing side facing the box is provided with a second engagement surface for the pair of pincers on which two opposing jaw members (1201, 1202) of the pair of pincers can be placed that take the connector between them for squeezing the cable carrier from the first position to the second position, wherein the box is provided with a continuing insertion channel extending above the second engagement surface for the pair of pincers for from the outer side of the box inserting the jaw member engaging onto the second engagement surface for the pair of pincers.