4.2 Routes of conductors, cables, and transmission linesa. The use of terminals, cable connectors or other electrical equipment within the ducting for electrical installations and cable ducts is not permissible.b. The terminal housing on the terminals provided must be dimensioned so that a sufficient bend radius can be complied with.c. Data transmission lines and bus cables are generally to be laid in separate cable channels. The use of existing cable channels is only permissible if the data lines and bus cables are laid so that they are isolated from the other cables by means of metal bars. Areas with double junctions require horizontal isolation (using metal jumpers).Cables and transmission lines are to be laid neatly in the cable ducts and in riser ducts; control cables and power cables are, in all cases, also to be laid in separate cable ducts.d. In areas that are not accessible during normal operation too, cables are to be installed so that no hindrances or permanent plastic deformations occur during maintenance and repair work.