substitute lines 29 in the absence of any voltage supply see fig4 the corresponding individual cables only comprise signal cable connections in the form of fiber cables 21 the ends of the individual cables according to fig7 are then separated with respect to voltage supply and signals see fig6 so that ten individual connectors for signals and ten individual connectors for voltage are present fig7 shows such an individual cable 27 on an enlarged scale comprising nine fibers 30 and being designed as a coaxial cable that simultaneously serves the transmission of the corresponding voltage hence it is possible according to the invention to feed several production apparatuses or production trees by taking minimal efforts only by way of one converter unit 2 and a corresponding control unit 3 to 10 is assigned to every production apparatus as a rule especially the saving aspect with respect to cable connections that are no longer needed is important according to the invention and it is particularly possible to control and regulate each of the production trees in real time on site and safety monitoring can be realized through the exchange of corresponding data this is also accomplished with a minimal number of units see e g a converter unit 2 connected to eight control units the corresponding control unit serves on site in the production apparatus for distributing power and the corresponding.