Choosing the most suitable clamping solution for distribution cables  

anchoring clamps for the roll-out of FTTH overhead cables on distribution networks

To ensure long lasting fiber optic overhead networks, a major importance should be attached to the compatibility between the clamp and the cable to be deployed. Indeed, in order to choose the most suitable network equipment for your needs and guarantee thus reliable dead-ending or suspension applications, it is essential to examine :

  • the entire installation environment
  • the associated constraints
  • the characteristics of the cable to be deployed

In FTTH network architecture, the distribution segment is the part of the access network connecting a Fiber Concentration Point (FCP) to an Optical Distribution Point. The point of departure for distribution cables is thus a street cabinet playing the role of an intermediate network node used for cross-connecting applications. Inside this street cabinet, telecommunications providers install splitters enabling thus to implement point-to-multipoint technologies (PON). As a point of flexibility in FTTH infrastructure deployment projects, the Fiber Concentration Point can be installed at the access or the core of a residential area so to ease subscriber connection, intervention and maintenance operations. The FCP can also be installed at the Point of Presence level for enabling connections to future subscribers living nearby.

Optical signal is hauled from a Fiber Concentration Point to an Optical Distribution Point thanks to optical distribution cables rolled out in overhead configurations with medium spans and presenting smaller diameters than feeder cables. These cables are then fasten at the top of utility poles used for LV networks or telecommunications poles with a medium span clamp, a short span clamp or a suspension device engineered for this purpose.

Depending on the population density and the network topology, distribution cables are deployed on more or less congested overhead telecommunications lines. In addition, climatic conditions represent another important constraint that should be considered when selecting the most suitable network equipment.

How to identify the right solution for anchoring distribution cables with round structure

Having the capacity to dissociate from other cables installed on overhead lines, ADSS cables are used both for installations on HV and LV lines and telecommunications networks. Lightweight and dielectrically stable, ADSS round cables are widely preferred for the deployment of access networks and particularly for the roll-out of distribution part. Comprehensive ranges of aerial cable clamps are available for round, self-supported and dielectric cable termination. Thus, for the dead-ending of round ADSS cables with rigid insulation and presenting diameters form 5 to 8mm and rolled-out on spans up to 70 meters, anchor clamps with enveloping wedges are a suitable technological solution. Engineered with a reinforced body and more enveloping wedges, these clamps fit perfectly onto the cable’s shape, while preserving the functional characteristics of the cable in case of overload.

For overhead line configurations with spans up to 90 meters, the dead-ending of ADSS distribution cables with diameters 6 to 14mm with HDPE insulator is ensured by compact ACADSS clamps. For the termination of round cables with larger diameters, from 9 to 19mm, ACADSS clamps are more suitable solutions as they offer a cable tightening over a total length of 230mm versus 165mm for compact clamps.

compact ACADSS clamps for round optical cables

The dead-ending of ADSS round cables can be also performed by using helical dead-ends such as GSDE without armor rod or the AADE with relieved ends. While the first ones are compatible with round cables with diameters from 10 to 21mm, the AADE spirals cover a wide range of round cable diameters from 6.2 to 15mm. Both of these ranges are designed for spans up to 90 meters.

Which accessories for anchoring figure-8 distribution cables?

There are also numerous solutions for the termination of figure-8 cables on poles or facades. For aerial configurations with spans that do not exceed 90 meters, three types of clamps have been developed to meet different mechanical constraints.

Standard anchor clamps for short spans offer a 200daN resistance et a cable tightening on a total length of 60mm, while anchor clamps with long body for short span aredcchanical resistances, of maximum 750daN, reinforced anchor clamps for figure-8 cables are more suitable technological solutions.

For the anchoring of figure-8 distribution cables with dielectric messenger deployed on spans up to 180 meters, it is recommended to use anchor clamps for figure-8 cables and long spans.

Choosing the right dead-ending clamp for flat distribution cables

For overhead lines with spans up to 70 meters, there are two dead-ending solutions: the drop conical clamp with plastic wedges designed for the dead-ending of flat cables with diameters up to 8x4mm and the wedge clamp especially engineered for the deployment of FTTH infrastructures by using flat cables with a diameter of maximum 7x3mm.

For spans up to 90 meters, drop clamps with elongated body included in the ODWAC range are more suitable. While the standard ODWAC clamp is designed for flat cables with maximum diameters of 9x4mm and a 100daN mechanical strength, the ODWAC XL clamp is used for the termination of cables with larger diameters, of up to 15x6mm and meets a mechanical resistance of up to 150daN. Thus, these range of drop clamps has been developed to meet the dead-ending needs of most of fiber optic flat cables.

Which accessory for the suspension of distribution cables?

For the fastening of overhead lines on intermediate poles, there are four technological solutions:

  • J hook suspension clamps
  • Mobile suspension clamps
  • Long span suspension devices

These devices, all compatible with round ADSS cables, are developed to meet different cable fastening needs. Thus, for spans up to 70 meters, JTP suspensions can be used either as fixed or mobile suspension solutions, while JHC clamps enable the cable unrolling directly into their body, once their elastomer sleeve is removed. Moreover, the JHC range covers a wide range of cable diameters from 5 to 20mm.

J hook suspension devices for fibre optic round and flat cables

Used both for the suspension of round cables and flat drops, the DS clamps suit for smaller diameters: 2 to 8mm.

For suspension applications on cables rolled-out on HV networks characterized by longer spans, of up to 180 meters, DSAL suspension devices are more suitable. These solutions are compatible with cable diameters from 8,5 to 21mm.