Planning the Route

Having decided to use fiber optics and chosen equipment appropriate for the application, it is time to determine exactly where the cable plant and hardware will be located. One thing to remember: Every installation is unique. The actual placement of the cable plant will be determined by the physical locations along the route, local building codes or laws, and other individuals involved in the designs. As usual, premises and outside plant installations are different, so we will consider them separately.

Premises installations can be simpler since the physical area involved is smaller and the options fewer. Start with a good set of architectural drawings and, if possible, contact the architect, contractor and/or building manager. Having access to them means you have someone to ask for information and advice. Ideally, the drawings are available as CAD files, so you can have a copy to do the network cabling design in your computer, which makes tweaking and documenting the design much easier.

If the building still is in the design stage, you may have the opportunity to provide input on the needs of the cable plant. Ideally, that means you can use your experience as an electrical contractor to influence the location of equipment rooms, routing of cable trays and conduits, availability of adequate conditioned power and separate data grounds, sufficient air conditioning and other needs of the network. For pre-existing buildings, detailed architectural drawings will provide you with the ability to route cabling and network equipment around the obstacles invariably in your way.

Sometimes you also have to work with other people who may influence the design. Information technology managers usually will have input on what their needs are now and in the future. Sometimes a structured cabling specialist may be involved who may or may not have experience with fiber, which is why you were brought in. Even company big shots may have an opinion, since many companies like to showcase their investment in fiber optics.

As soon as possible, visit the site. For current buildings, inspect every nook and cranny to be absolutely certain you know what the building really looks like, and then mark up drawings to reflect reality, especially all obstacles to running cabling and hardware and walls requiring firestopping that are not on the current drawings. Take pictures if you can.

For buildings under construction, a site visit still is a good idea, just to get a feeling of what the final structure will be like and to get to know the construction managers you will be working with. They may be the best source of information on the local authorities who will be inspecting your work and what they expect in the final construction.

Outside plant (OSP) cabling installations have enormous variety depending on the route the cable must take. The route may cross long lengths of open fields, run along paved rural or urban roads, cross roads, ravines, rivers or lakes, or, more likely, some combination of all these. It could require buried cables, aerial cables or underwater cables. Cable may be in conduit, innerduct or direct buried. Aerial cables may be self-supporting or lashed to a messenger. Longer runs often include crossing water, so the cable may be underwater or be lashed across a bridge with other cables.

With all those options on OSP installations, where do you start? With a good map. Not just a road map or a topographical map, but satellite images overlaid on roads is much better—the type Google Maps can provide. Creating a route map is the first step, noting other utilities along the route on that map and checking with groups that document the current utilities to prevent contractors from damaging currently installed pipes and cables.

Once you have marked-up maps, the real fun begins—finding out whose permission you need to run your cabling. OSP installs are subject to approval by local, state and federal authorities who will influence heavily how your project is designed. Some cities, for example, ban aerial cables. Some have already buried conduit, which you can use for specific routes. Since many municipalities have installed city-owned fiber networks, they may have fiber you can rent, rather than go through the hassle of installing your own.

Unless you are doing work for someone at a utility who already has the contacts and, hopefully, easements needed, you may get to know a whole new set of people who have control over your activities. And you have to plan for adequate time to get approval from everyone who is involved.

If all this sounds vague, it is. Every project is different and requires careful analysis of the conditions before even beginning to choose fiber optic components and planning the actual installation. Experience is the best teacher.

HAYES is a VDV writer and educator and the president of The Fiber Optic Association. Find him at

About the Author

Jim Hayes

Fiber Optics Columnist and Contributing Editor
Jim Hayes is a VDV writer and trainer and the president of The Fiber Optic Association. Find him at .

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