Tops for laying cables

Cables must be selected to suit the operating conditions. They must be protected against mechanical, thermal or chemical impact and against the ingress of moisture from the line ends, or to be developed from the outset to resist adverse environmental conditions.

Insulated high-voltage wires may not be laid underground. Temporary covering of rubber-sheathed wires or trailing cables with earth, sand or similar material, e.g. on construction sites, is not considered laying underground.

Fasteners of stationary wires and cables must not damage the wires or cables. If cables or wires are fastened horizontally along walls or ceilings, then the following guidelines for clamp spacing apply: For non-reinforced cables and wires, 20 x outer diameter. This spacing also applies for support sites when laying on cable racks and frameworks. For vertical laying, the clamp spacing can be larger, depending on the type of cable and clamp.

Flexible cables connected to mobile power consumers must be protected at the point of entry against push and pull forces (strain relief) and protected against torsion and kinking. The outer sheathing of the wires must not become damaged at the points of entry or by the strain relief mechanism.

Flexible rubber-sheathed wires are only suitable for permanent outdoor use if the sheath material consists of a mixture based – as a rule – on polychloroprene. For permanent use under water, special wires must be used. Feel free to ask us – will will gladly advise you!

Tensile stress

The tensile load on the conductor must be as low as possible. The tensile stresses stated below must not be exceeded on the conductors in cables.

  • When laying copper wires for mobile equipment, 15 N per mm² conductor cross-section, where shielding, concentric conductors and divided protective conductors are not factored in. For wires that will undergo dynamic stresses during operation, e.g. in crane systems with high acceleration or cable drag chains under frequent motion, suitable measures must be specified, e.g. larger bending radii in individual cases. In some cases, it must be assumed the lifespan will be shortened.
  • When laying stationary wires, 50 N per mm² conductor cross-section.
  • For fibre-optic, BUS, LAN, industrial and Ethernet wires, the respective permissible stresses must be observed. These specifications are provided in the respective product datasheets, or are available at request.