WCA November 2011

Riser cable

Strain gauge

Misalignment

Pulling direction

Pulling grip

Duct

Duct

Gap size

❍ ❍ Figure 4 : Testing setup

All connectors and the breakouts on the floor level are factory assembled and therefore avoid the critical step of a typical mid span access of the cable. The cable is already 100% factory tested before being delivered to the deployment site ie MDU. The riser assembly is built according to the exact individual MDU architecture. Only very basic parameters like the distance between floors (F) and the distance from the basement distribution terminal to the first floor breakout point (B) have to be provided in order to enable this ( Figure 2 ). Based on this information even installers not used to handling fibre can deploy the proposed cable very quickly. The basement tail length is predefined at 120cm for easy connection into the basement distribution terminal. The length of the individual breakout tethers at the floor level depends on the given floor height (F) and are predefined as F-15cm as the maximum length. In order to minimise the cable diameter during installation the connectors at each floor level are staggered along the main cable during the installation procedure. The cable assembly comes with a pulling grip for easy installation. The extension distance from the last tap point to the pulling grip is predefined at 5m. Different connector types such as SC or LC can be chosen for the complete assembly.

OD = 7.6mm

OD = 9.0mm

❍ ❍ Figure 3 : Micromodule cable (up to 144f)

1 Riser cable assembly The recent emergence of single mode fibres for FTTH applications with improved bending performance has been driven by the increasing amount of optical cable being installed inside buildings with all the associated bend challenges. As mentioned before, the speed of deployment creates another main challenge in today’s installations and the pre-connectorised riser solution has been specifically designed to overcome this issue. As the FTTH scale of deployment increases, customers will have trouble finding enough skilled splicing technicians. Additionally, labour rates for highly skilled fibre craftsmen are already increasing. The proposed solution enables considerable advantages in the speed of deployment, while significantly decreasing the number of skilled installers needed to complete an installation successfully. Faster deployment time will allow customers to generate revenue faster, thus increasing their ROI. The main element of the proposed solution is a pre-connectorised riser cable shown schematically in Figure 1 . This solution is based on bend insensitive fibre, which makes it ideal for deployments within the challenging MDU environment. The riser assembly provides single connectors (SC or LC type) on the basement side to be connected to a basement distribution terminal and individual fibre breakouts on each floor level to be connected to the individual customer apartments.

❍ ❍ Figure 5 : Pulling force vs Duct fill ratio

PF Pulling force [N]

Duct fill ratio [%]

56

Wire & Cable ASIA – September/October 2007 Nove ber/De ember 2 11