Zone cabling for cost savings

Today’s enterprise workspaces are increasingly social and flexible, and are subject to frequent reconfiguration and updating. To determine how structured cabling can best support flexible workplaces, Siemon recently analysed the cost and environmental impact of various structured cabling designs. Below are the findings.

Siemon found that zone cabling deployments provide the optimum balance of performance, flexibility and efficient use of cabling materials in today’s enterprise environments. 

A zone cabling design (or topology) begins with horizontal cables run from patch panels in the telecommunications room (TR) to connections within a zone enclosure (ZE, sometimes referred to as a zone box), which can be mounted under a raised floor, in the ceiling or on the wall. Cables are then run from the outlets or connecting blocks in the zone enclosure to telecommunications outlets in the work area (WA), equipment outlets serving BAS devices or directly to BAS devices. Patch cords are used to connect voice and data equipment to telecommunications outlets and to connect BAS equipment-to-equipment outlets.

The connections in the zone enclosure are made using modular outlets and/or punch down blocks - there is no active equipment in the zone enclosure. When deploying a zone cabling solution, zone enclosures must be positioned in the most densely populated areas of the floor space. 

What is zone cabling?

Enabling flexible client workspaces that efficiently accommodate moves, adds and changes (MACs) is a signature element of a zone cabling design. Through analysing a customer’s office reconfiguration needs, zone cabling deployments have the potential to provide significant cost savings compared to traditional ‘home run’ work-area-to-TR cabling. This is because MACs performed on traditional home run topologies require more cabling materials and more installation time to implement.

Quantifying the cost savings

Siemon designed traditional and zone cabling layouts for a typical one-floor commercial building space, then analysed the capital and operating costs associated with each design. For the purpose of this analysis, the traditional cabling topology scenario provided two outlets to 36 work areas for a total of 72 cables or ‘drops’ and the zone topology scenario provided two outlets at 36 work areas and 72 connection points in a zone enclosure, plus an additional 24 cables pulled to the zone enclosure to accommodate future expansion.

To establish a baseline, Siemon first calculated the material and installation costs for the category 5e UTP, category 6 UTP, category 6A UTP, category 6A shielded and category 7A shielded traditional (72 drops) and zone (96 drops to the zone enclosure and 72 drops to the work area) cabling designs, and plotted the results shown in Figure 4. Since zone cabling is commonly deployed in the ceiling where air-handling spaces are prevalent, media costs were derived using plenum rated materials where applicable. Not surprisingly, the total cost for the zone cabling design is higher than the cost for the traditional design, because there is additional connectivity in each channel and some pre-cabling between the TR and zone enclosure is included for future connections.

Although additional capital expenditure (CAPEX) is required when zone cabling is initially deployed, a more accurate assessment of the total comparative costs of these solutions must include operating expense (OPEX). MAC work performed on a cabling plant falls into the category of OPEX and it is in this area that the real cost benefits of a zone cabling solution become apparent. For this analysis, a cabling ‘add’ represents the cost to pull one new cable and a cabling ‘move’ is the cost to pull one new cable and remove the abandoned cable. The table in Figure 5 depicts Siemonʼs calculated cost savings per move or add for all of the categories of cabling evaluated and the number of MACs that need to be performed for the combined CAPEX and OPEX cost associated with the traditional cabling design to equal that of the zone cabling design.

This tipping point is often referred to as the time when return on investment (ROI) is achieved for a zone cabling design. Enterprise clientsʼ IT requirements are dynamic and often require rapid floor space reconfiguration. Due to their enhanced ability to support MACs, building owners can realise a significant ROI benefit with their zone cabling systems within two to five years compared to traditional cabling systems. According to the cost analysis, either 14 moves and 17 adds or 16 moves and 20 adds (depending upon cabling type) will realise a full ROI of the additional CAPEX for a zone cabling solution and each MAC above the ROI threshold yields additional OPEX benefits over a traditional cabling design.

Depending on the number of MACs performed, a zone cabling design can pay for itself quickly. Figure 6 shows that the combined CAPEX and OPEX costs for all category zone cabling designs are always lower than for traditional cabling designs after 16 moves and 20 adds are performed, and there is still flexibility to add additional services to the zone cabling design.

Zone cabling ROI

The results of this analysis may be extrapolated and applied to small, medium and large zone cabling installations.

In addition to the obvious cost benefits, deployment of zone cabling provides the following additional benefits:

• Factory pre-terminated and tested trunking cables may be used for expedited installation and reduced labour cost.
• Spare ports in the zone enclosure allow for the rapid addition of new devices and facilitate moves and changes of existing services.
• Pathways are more efficiently utilised throughout the building space.
• Deployment of the structured cabling system is faster and less disruptive.
• New IP devices, such as WAPs, BAS devices, voice/data security devices, audio/video devices, digital signage, etc, are easily integrated into the existing structured cabling system via connections made at the zone enclosure.

Going green

Zone cabling systems are suitable for use in smart and green building designs. Factory pre-terminated trunking cables can be installed for a reduction in labour costs and on-site waste, and the centralised connection location within the zone enclosures allows for more efficient pathway routing throughout the building.

Integrating cabling systems into a zone topology allows customers to further take advantage of cable sharing strategies. Cable sharing supports multiple low-speed, low-pair-count applications operating over one 4-pair cabling system, which results in more efficient cable and pathway utilisation.

Top image credit: ©iStockphoto.com/Ola Dusegard