The Secret Lives of Enclosures and Pedestals

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(This article originally ran in OSP Magazine)

When President Barack Obama signed into law the American Recovery and Reinvestment Act (ARRA), service providers couldn’t help but wonder how they might benefit from the 7 billion dollars tagged for broadband initiatives. As providers prepare their proposals to the NTIA and RUS for consideration, many internal questions must be addressed about outside plant (OSP) infrastructure. Fiber networks are as varied in their physical structure as the broadband content they deliver. Yet providers know that preference would be given to shovel-ready projects that could help bring broadband to those unserved and underserved corners of the nation’s network while creating immediate job opportunities for the telecommunications industry. With this in mind, many providers turned to an old friend, the buried distribution pedestal, for new answers to deploying FTTP quickly and cost-effectively.

Early fiber deployments relied largely on buried vaults and metallic cabinets at splice points and cross-connects. Below-grade vault enclosures served to protect sealed fiber splice cases at fiber drop points. Larger metal cabinets housed fiber interconnect and cross-connects.

However, both buried vaults and metal cabinets had limiting drawbacks. Vaults are not easily accessible and require substantial labor to install. Metal cabinets presented even more deployment hurdles, often requiring poured concrete pad bases, placement above floodplains, and the obtainment of right-of-way (ROW) permits before placement could be made.

Providers soon realized that more compact solutions with greater flexibility in placement were needed. It was then that pedestal manufacturers began approaching providers and working with them to design unique environmentally sealed enclosures based on the familiar copper pedestal architecture. Above-grade, non-metallic fiber pedestals have evolved rapidly in the last five years to include a wide assortment of FTTP enclosures capable of supporting virtually every type of fiber architecture.

The portfolio of fiber pedestal solutions now available to service providers includes fiber distribution points, interconnects, flexibility points, enclosures for sealed splice cases, and slack storage housings. Fiber pedestals now service such diverse applications as
cell sites, multi-dwelling units, strip malls, residential neighborhoods, and rural locations.

Types of Fiber Pedestals

The most common type of fiber pedestal is the distribution point, often used as the splice point near residences with drops from the pedestal extending to optical network terminals (ONT) mounted on the customer premises.

Pedestal manufacturers realized that by creating new backboards inside their pedestals that accommodate mounted splice trays, organized fiber management, and fiber-specific bonding/grounding and cable attachments, they could offer service providers a low-cost, environmentally protected distribution point. (See Figure 1.) A pedestal solution also helped speed deployment. Contractors and installers were already familiar with their installation practices and procedures, and their easily re-enterable lift-off domes saved technicians valuable time when provisioning drops to new customers.

            

With the many different types of Passive Optical Network (PON) architectures being deployed, pedestal manufacturers made accommodations for the varied fiber networks they encountered. Buried distribution point pedestals were modified to accept both stranded and ribbon fiber. Fusion and mechanical splicing arrangements were supported, as well as pre-connectorized drops and sealed fiber terminals. Pedestals proved to be extremely adaptable to both brownfield and greenfield deployments. Some manufacturers even began offering composite copper/fiber pedestals capable of supporting copper splices on ladder bars on one side of the pedestal backboard and fiber splice trays on the other.

Manufacturers also rationalized that varying levels of protection were required by different providers, and created multiple pedestal architectures to balance the cost/protection dichotomy. For providers requiring fiber enclosures meeting GR-771-CORE requirements, closed architecture pedestals were designed to include a sealed inner splice compartment in addition to the domed enclosure. While costing a bit more, providers were able to achieve the highest levels of environmental protection and network reliability. Where first cost is a major consideration, open architecture pedestals that meet RUS approval are available. These lower-cost alternatives provide a high degree of environmental protection, including flood, fire, dirt, and rodent resistance, with an open access to the splice compartment.

Realizing their cost savings compared to metallic cabinets, providers urged manufacturers to develop pedestal solutions for other common fiber network needs, including interconnect and centralized split points. Pedestals manufacturers responded by creating fiber pedestals that could function as cross-connects and fiber distribution hubs. The compact size pedestals was ideally suited to small communities and neighborhoods where large metallic cabinets were overkill, both physically and financially, due to their unnecessarily high capacity in low population areas. Pedestals also proved to be well suited for cell site and strip mall applications due to their flexible placement and smaller footprint.

Fiber interconnect pedestals were designed to provide pre-connectorized interconnect panel fiber drops to multiple broadband service customers. As a replacement for passive fiber cross-connects, interconnect pedestals are deployed at cell sites, strip malls, campus environments, multi-dwelling units, and other multi-tenant sites. They are often used for wireless backhaul and private networks. Interconnect pedestals facilitate fast and easy provisioning of fiber services to the multiplexing equipment through their built-in pre-connectorized adapter bulkheads. Fiber drops can be turned up, moved, or disconnected on an as-needed basis, giving providers flexibility in environments where customers’ bandwidth requirements may change seasonally or as a result of periodic planned events.

Fiber flexibility pedestals are most commonly used at neighborhood entrances, providing a pre-connectorized point where service can be turned up to individual premises quickly and easily. (See Figure 2.) These pedestals include an interconnect panel with pre-stubbed feed and distribution cables. An interconnect panel with discrete splitter modules offers a grow-as-you-go scalability that allows providers to defer costs by adding capacity and turning up subscribers on an as-needed basis. In areas such as co-ops, where high take rates are assured, a low-cost alternative is also available with a standard fiber pedestal housing splitter trays instead of splitter modules.

Larger capacity splice housings for buried plant were also introduced as an above-grade alternative to buried vaults typically used for slack storage and storage of sealed fiber splice cases. These fiber multi-purpose housings feature generous internal volumes and sturdy mounting rails for attaching splice cases, stubs, and slack cable.

The Impact of Fiber Pedestals on Stimulus Projects

As providers gear up for projects funded by the ARRA, fiber pedestals will play an important role in the PON architecture projects that will help bring broadband to hundreds of thousands of new customers and stimulate jobs for the telecommunications industry. Fiber pedestals meet many of the guiding objectives of the stimulus plan. They fit nicely into shovel-ready projects since they do not require ROWs, and have a high degree of flexible placement. They contribute to keeping labor a low percentage of the total cost of a build.

Perhaps most importantly, they are designed for a long lifecycle to keep our nation’s broadband highway functioning reliably for years to come. In this belt-tightening economy, pedestals offer providers a tangible means of keeping first cost and lifecycle costs as low as possible when it comes to their fiber distribution needs. Especially in rural areas, pedestals offer a right-sized solution that makes sense for both fiber overbuilds and greenfield projects.

When evaluating pedestals for use in fiber builds, providers must first answer the above-grade/below-grade question. Unless below-grade builds are required by local ordinances, the advantages of accessibility, flexible placement, quick deployment and lower costs are often enough to convince providers to opt for an above-grade solution. Providers choosing an above-grade approach must then proceed through a checklist of items, including cable type (central core, loose tube, composite), fiber type (stranded, ribbon), terminations (fusion splice, mechanical splice, pre-connectorized, sealed fiber terminal) and deployment architecture (stub-fed, loop through, branch, drop) to determine the right pedestal for their individual application.

With ARRA plans calling for fund allocations to begin by the end of 2009, providers are working hard to put their best foot forward and submit project considerations that meet the dual purposes of creating jobs and forwarding the vision of universal broadband coverage in the United States. Fiber pedestals may represent only one component in the larger picture of a total fiber buildout, but nonetheless it is an important one.

Pedestals contribute significantly to the survivability and reliability of our nation’s broadband pipelines. They are especially useful in bringing high-speed voice, data, and video to the hard-to-reach areas that the NTIA and RUS prioritize. As we look forward to the many new enhancements to the nation’s broadband network and new jobs for our industry spurred by ARRA legislation, it is reassuring to know that pedestals, with their long legacy of protecting providers’ OSP investments, are playing their part.

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