Futureproofing a communications wiring system today is difficult. A successful cabling system must be designed and implemented with the intention of integrating voice/data/ video traffic for both now and the future.
Futureproofing communications cabling enables the system to cost effectively support a broad range of applications and systems. This gives the owner the control to administer current networks and migrate to future applications as required without re-cabling.
Compliance with standards and electrical codes is required for a cabling system to be successful. Guaranteed performance also has to be considered when providing a communications cabling system. The most important factor in futureproofing a cabling system is cost effectiveness. The objective of futureproofing a wiring system is to reduce the cost of owning a cable plant. Cost of ownership must be included as a major factor for a successful cabling system.
Design considerations: Start with a scope of work
The first requirement for the design of a successful communications cabling system is a Scope of Work. The Scope of Work defines connectibility requirements and methods to achieve them by the design and subsequent implementation.
The Scope of Work will address three specific stages: perceptions of what the requirements are and a conceptual design that fits these requirements; a perception of the conceptual design and how it would be implemented to fulfill requirements; and the actual design and specifications for the cable plant.
The Scope of Work provides, for all parties including the building owners involved, to begin with a clearly defined conceptual design and then work through the specifics of explicit design parameters and implementation of the design.
A key part of the Scope of Work development is careful analysis of all available drawings, a detailed walk-through, documents, specification requirements, and conversations concerning the facility to develop a clear Scope of Work that fulfills perceptions of all concerned parties. The Scope of Work is an extension of the analysis process. It is the first step in the design process provides form and substance to meeting needs and wants. The Scope of Work also forms the basis of development of an implementation plan for both current and future requirements.
Specify system and applications requirements
It is critical to specify the types of networks (Token Ring, Ethernet, fiber distributed data interface (FDDI), private branch exchange (PBX), asynchronous transfer mode (ATM), Fast Ethernet, Gigabit Ethernet, etc.) with the design requirements, because these networks dictate which type of cabling is required. Hubs and multiplexers must also be included because they require power and connectivity to backbones. Network electronics are more commonly included in the cabling bid. The key to understanding the design process is the concept of the network requirements determining the cable plant, not the reverse. For design purposes, it is helpful to list the communications requirements on a floor-by-floor basis. This helps avoid mistakes in the requirements of the design process.
To avoid making mistakes in the design process and ensure requirements are met, it is helpful to:Specify network types; Understand that equipment requirements dictate cable requirements; Include all electronics requirements: hubs, PBX, switches, multiplexers; Include network requirements: communities of interest, traffic load, utilization; and map out the design floor-by-floor.
Consider architectural items in relation to communications requirements
A building's architecture has to be perceived as dynamic. Over the years, many changes will be made to a building. Even newly constructed buildings change during construction.
In addition to architectural changes, communications systems performance requirements change with time. To ensure success, both architectural and communications requirements must be in harmony. When designing or upgrading a communication's cabling system, a seven- to ten-year life should be anticipated.
Architectural items to consider for communication cabling systems include: pathways, electromagnetic interference (EMI), distribution closet placement and size, useful life of cabling, grounding and bonding, and growth. For more information on architectural requirements for communications systems, see the TIA/EIA 569-A standards and the National Electric Code.
Communication cabling is routed both vertically and horizontally via pathways. For a new building, the pathways must be considered in the design. For existing buildings, available pathways must be identified, then either worked with or replaced by constructing new ones. The rule for (EMI) is no joint facilities, which means that high-voltage and low-voltage systems do not share the same spaces. Also, items such as motors, lights, machinery, and broadcast systems should be taken into consideration for sources of EMI/radio frequency interference (RFI). For new construction, the placement and size of distribution closets should be incorporated into the building design. With existing facilities, you have to either work with what is there or do modifications.
Grounding and bonding is a necessary design element for a new facility (in a campus situation, all buildings should have a common grounding system). The existing system should be inspected and upgraded if required. Future requirements that usually include growth must be considered for both new and existing facilities. The rule here is, design for the facility's maximum capacity, not immediate requirements.
Calculate the cost of ownership
To understand and appreciate facilities requirements, realize their cost. According to the IEEE (April 1991 Communications Magazine), the telecommunications utility is estimated at the following rough costs: lighting $3 per square foot, electrical $5 per square foot, and telecommunications $8 per square foot. This estimate states the costs to provide telecommunications to a work location are $800 (assuming 100 square feet per work area). The Intelligent Building Institute estimates the telecommunications utility can comprise 10 percent or more of a building's cost. It is estimated that all the components including the cable plant required to support a work location (network, LAN, PBX, cabling, computer, software, etc.) cost $5,300 per work area.
Along with equipment costs, cable plant administrative costs have to be considered. Administration consists of two parts: move, adds, and changes (MAC) and Problem Resolution. MAC activity varies depending on the organization. MAC accounts for between 30 and 100 percent per year. It is generally accepted that 70 to 90 percent of all problems are cable related and 80 percent of the resolution time for network repair is spent locating the circuit and equipment.
The combined cost for MAC and Problem Resolution for an undocumented single telecommunications outlet is approximately $600 per year. These costs will continue and more than likely, increase with time. These high costs are due to many items directly related to poor planning. These costs can be significantly reduced 25 to 75 percent by good planning, design, documentation, and administration.
Ownership costs can be reduced even more dramatically. For example, if it costs $5,300 per work area / $53 per square foot and you document cable-related administration costs, then cost of ownership can be reduced up to 90 percent.
Flexibility: Key to futureproofing a wiring system
It is becoming obvious that the key to a futureproofed network is a flexible communications wiring system. To obtain this, consider the rapidly changing pace of networking bandwidth requirements.
Today we are at 100 Mbps (100BaseTX, FX); right around the corner is 802.3z Gigabit networks operating at 1 Gigabit. Soon to follow 1 Gbps are the 10 Gbps networks. The next step after gigabit networks is terabit, which are currently being announced as available products. With today's rapidly changing technology, a 12-month cycle is stressing the capabilities of many communications wiring systems.
A successful communications cabling system is based on dynamic modular subsystems that can accommodate the rapid changes in communications technology. The subsystems, while independent, are implemented to compliment each other. Each subsystem is based on quality products that will support both current and future communications requirements (voice, voice over internet protocol (VoIP), video, data). The subsystems provide connectivity and power from the building entrance to the end user's desktop. A successful wiring system provides systems transparency for both current and future applications.
Communications equipment uses complex, delicate, and sophisticated microprocessor circuits; therefore, treat it as delicate instruments.
Power disturbances are a major cause of network outage and equipment damage that costs billions of dollars per year. Unfortunately, power quality is often overlooked, since many designers do not consider or are not aware of power quality as a concern for operation and design of a communications network.
Networked devices require more sophisticated power quality than stand-alone computers and other electronics. This makes power quality a serious concern for both current and future network operations. The major problems associated with power quality for communications devices are common mode disturbances, harmonics, grounding/bonding, circuit loading, and electrical protection. UPS systems must also be considered as integral to power quality.
Rapidly changing network technology and constant moves, adds, and changes complicate futureproofing of communications wiring systems. The best way to address futureproofing a wiring system is to address the two most stable items in a wiring system; the pathway and power quality.
Seriously consider using access floor systems for both electrical and communications distribution. These systems provide the most flexible and stable of pathways; even if the walls are torn down, an access floor system will remain intact. Since the typical method of pathway is above the ceiling, which offers very little ability to futureproof when walls are removed. The walls that support the wiring are directly connected to wiring in the above-ceiling pathway. Selecting a cable type: Category 5, 5e, 6 and fiber optics to the desk (multi and/or single-mode) is a concern, and establishing a flexible pathway is critical.
Since nonlinear loads are detrimental to electrical systems, and their source is communications equipment, k-rated transformers with properly sized neutrals are essential to a communications system's longevity. Along with k-rated transformers, isolated ground outlets should be considered to protect both current and future networked devices. Last of all, ensure that the facility and equipment grounding systems are correct.
A futureproofed wiring system includes many systems that are unique to electrical contracting. So, you can futureproof your electrical contracting business by becoming involved with communications wiring systems.
Subsystems of Structured Wiring System
Work location is the designated cable quality and continuity (number of pairs) needed to connect the terminal equipment to the Telecommunications Outlet. It consists of station mounting cords, outlet, pin-outs, etc.
Horizontal wiring consists of the designated continuity needed from the user's telecommunications outlet to the distribution closet. Tie cables between floor closets on the same are considered as horizontal wiring regardless of their physical characteristics (fiber, unshielded twisted pair (UTP).
Backbone is the central or feeder group of cables in a building. This cable is typically placed from the Main Cross-connect TC to other floors where it is terminated in Intermediate TCs.
Equipment wiring consists of the cables and connectors that link communications systems, host computers, local area networks (LANs), and other devices to shared equipment or cross and inter-connects at the TCs.
Campus subsystem is the cabling that runs between buildings on a campus.
Administration consists of the wiring and equipment used to administer the interconnectivity between wires or cables and the associated electronics. The primary components of this system are the termination blocks and the cross-connect jumper wires and/or patch cords. Along with the wiring and equipment, construction documents (labeling and cable records) are also an integral component of this subsystem.
SCHECKLER is an instructor with Technology Standards Group, Inc. He may be reached at firstname.lastname@example.org.