How to ensure the cable - clamp compatibility ?
To develop reliable and future-proof telecom networks it is essential that the selected anchoring and suspension solutions to be qualified for the type of network on which they will be installed. The mechanical connection between a clamp and the cable to roll-out is an important issue for overhead networks. A suitable aerial cable clamp must be able to ensure an effective cable grip, without damaging the sheath of the cable or having any impact whatsoever on the quality of the transmitted optical signal. To ensure the compatibility between an anchor or suspension clamp and the outdoor cable, three main criteria are to be considered:
- the cable’s structure
- the cable’s diametere
- the span length of the network to roll-out: the longer the span, the longer the clamp’s bail. This will enable to avoid any contact between the clamp’s bail and other elements and most importantly, to respect the cable’s bend radius when this one is used in configurations consisting of creating a small loop above or underneath the pole’s top.
For telecommunications feeder networks, characterised by greater span lengths, helical dead-ends offer a better cable grip thanks to their large contact surface with the cable.
The compatibility between dead-ending solutions and cables to deploy is checked by carrying out the following qualification tests:
- Tensile test at the short-term tensile load of the cable (Maximum Allowable Tension) according to EN 60794-1-2 standard - modified Method E1, involving a couple of anchoring devices on a cable length greater than 1 meter. The
compatibility between the telecom anchor clamp and the aerial cable is established when there is no slippage of the cable inside the anchoring clamps, no deterioration of the cable, nor deterioration of the signal (attenuation
less than 0.1dB) .
- Galopping test for anchor clamps according to EN 60794-1-2 standard - Method E1. This consists into applying 10 undulations to cables with a smaller or equal diameter to 6mm (drops), 3 undulations to cables with a greater diameter than 6 mm (distribution and feeder cables) and a measurement of optical losses for 300 hours. A test is considered conclusive when registered optical losses are less than 0.1 dB throughout the test.
Solutions for overhead round self-supporting cable
Depending on the part of the network to be rolled-out, various technological solutions are available for deploying an overhead telecom network:
- For last mile access network: :
There are many different models of anchor clamps for ADSS cable. Conical clamping dead-endings such as those included in the AC range for example are intended for spans up to 70 meters. These anchor clamps are designed with more enveloping wedges so to fit perfectly onto the cable’s shape and to preserve its functional characteristics in case of overload. As for wedge clamps, they enable simple or double dead-ending of round drops with small diameters on poles or walls. Mandrel devices are another fastening solution for aerial drop roll-outs. Especially designed for the dead-ending of drops with flexible and insulating outer sheath, these anchor clamps present a mandrel body in which cable can be coiled and self-tighten.
- For distribution network:
Anchor clamps included in the ACADSS range are overhead cable fastening solutions enabling to start, realise dead-ending applications all along and to terminate telecom distribution networks where spans do not exceed 90 meters. Offering an effective cable grip, ACADSS clamps do not exert any bending radius stress on the cable. Another solution for effectively anchoring round cables on distribution networks is to opt for helical dead-ends using the preformed technology. While GSDE spirals install only on telecommunications networks, helical dead-ends from AADE range can also be used for intallation on low voltage power networks. Both of these spirals are developed for spans of maximum 90 meters.
- For feeder network:
For greater spans, such as for those commonly met on feeder networks, dead-ending applications must be performed with fastening devices engineered to resist to higher tensile strengths. Designed with armor rods, helical dead-ends from GSDE AR range preserve telecom cables deployed on spans up to 180 meters from bending, compression or abrasion.
Solutions for overhead figure-8 cable fastening
For the roll-out of figure-8 cables with dielectric messenger on spans up to 90 meters, several technological solutions are available as well. Drop clamps AC35 and AC68, for example, present a compact body and a tensile strength of 200daN, while AC L anchor clamps are designed with an elongated body for a maximum tensile strength of 300daN. For superior tensile strengths, discover ACFO anchor clamps with reinforced body. For longer spans reaching up to 180 meters, choose anchor clamps providing for even higher tensile strengths such as the ACAL clamps, engineered with aluminum body.
The dead-ending of figure-8 cables or aerial figure-8 duct structures with steel messenger can be performed with AC anchor clamps. To terminate figure-8 cables with steel messenger deployed on spans of up to 90 meters, parallel groove clamps can also be used.
All along the feeder, distribution or last mile access network, suspension applications for figure-8 cables can be realised with SC clamps. Available in various models, these cable fastening devices enable a fixed or articulated suspension.
Solutions for overhead flat cable fastening
Optical flat cables deployed on spans up to 70 meters can be fasten and secured on poles with Hypoclamp F clamps. These anchoring devices enable an effective grip for most of fiber optic flat cables thanks to their carefully selected component materials. The 5/35 FTTH anchor clamp is another solution for performing dead-ending applications on flat cables deployed on distribution or last mile access networks. This device enables the manual sag adjustment. An alternative to these two listed technological solutions is brought by the ODWAC clamp range. This includes two versions so to meet a wide range of cable diameters and various needs of tensile strength.
For the deployment of flat cables on telecommunications networks or LV power network infrastructures with spans of up to 180 meters, DSAL clamps are effective solutions of mobile suspension as their installation is simple, fast and safe. DSAL suspension devices are also compatible with a large range of ADSS round cable diameters. For spans shorter than 70 meters, DS clamps are befitting for enabling mobile suspensions. Their lightweight and cost-effective design has been especially developed to provide high mechanical performances for an installation on last mile access networks.