The electrical utility industry is increasingly dependent on high-speed optical networks to assist daily operations. For more than two decades, utilities used fiber optic media to support their own internal applications. In more recent times, public power companies plus an occasional electric cooperative have ventured into FTTH cable production line for the benefit of their clientele and also the generation of additional revenue streams. In the future, new construction and smart grid initiatives promise to expand fiber’s role even farther into electric utility operations. The very last point is quite a statement considering that fiber is located on transmission lines and distribution lines, in generating stations, as well as substations.
So, should it be a particular that optical fiber is a reality from the electric utility industry, then its essential for those with responsibility to the management of utility assets to understand a number of the basic groups of optical cable products and where those products best fit in the electric grid. Since many of the fiber used by utilities is deployed in the outside-plant, among the most common questions center around selecting ribbon versus conventional loose tube cable designs and where one solution is much more economically viable than the other.
Outside plant cables, either aerial or underground, get nearer to the house.
Both ribbon cables and conventional loose tube cables are staples of the telecommunications industry and have been popular for several years. Both products work well in harsh outdoor environments, and both can be bought in numerous configurations, including: all-dielectric, armored, aerial self-supporting, etc. The main distinction between those two product families will be the manner in which the individual fibers are packaged and managed within the cable. A ribbon cable offers the individual fibers precisely bonded together in a matrix that might encompass as few as four or as much as 24 fibers. Typically, however, these matrixes, or “ribbons” are bonded together in a team of 12 and placed inside a tube that holds multiple ribbons. In comparison, a loose tube cable design has between 2 to 24 individual fibers housed in multiple buffer tubes with each fiber detached from the other.
Pretty much anyone in the electric utility industry with any degree of contact with optical fiber products will be informed about the basic structure of loose tube cable. Ribbon cables, however, have enjoyed widespread adoption among regional and long-haul telephony providers but might still be unfamiliar for some inside the electric utility space. This unfamiliarity comes with a price since ribbon products can offer a four-fold edge over loose tube designs in several applications:
Ribbon cable can be prepped and spliced much more rapidly than loose tube cables. This advantage means less installation time, less installation labor cost, and considerably less emergency restoration time.
Ribbon cables enable a lesser footprint in splice closures and telecommunications room fiber management.
Ribbon cables offer greater packing density in higher fiber counts which enables better usage of limited duct space.
Ribbon cables are generally very cost competitive in counts above 96 fibers.
The very first two advantages mentioned above are byproducts of your mass fusion splicing technology enabled by ribbon cable. A mass fusion splicer can splice every one of the fibers in the ribbon matrix simultaneously. Thus, if your 12 fiber ribbon is utilized, all of those fibers can be spliced in approximately 12 seconds with average splice losses of .05 dB. In contrast, the standard loose tube cable requires each fiber to be spliced individually. So, by way of comparison, Optical fiber coloring machine requires 12 splices just to be fully spliced while a 144 fiber count loose tube cable needs a full 144 splices. In addition to the time savings, a decreased total number of splices also yields a decrease in the quantity of space required for splicing. Hence, there is an associated reduction in the quantity of space necessary to support splicing in closures and then in telecommunications room fiber management.
The reader with experience using ribbon cable might offer two objections at this point. The first objection is the value of mass fusion splicing equipment, and also the second objection would be the painful and messy procedure of prepping large fiber count unitube ribbon cables. The initial objection is easily overcome by simply checking out the current prices of mass fusion splicers. Over the past number of years, the fee difference between single-fiber and ribbon-fiber splicing equipment has decreased dramatically. The 2nd objection has become overcome through the development of all-dry optical cable products. Older ribbon cable products were painful to prep due to the infamous “icky-pick” gel used to provide water-blocking. The unitube form of many ribbon cable products translated into too much gel and a general mess to the splicing technician. However, new technologies allow both conventional loose tube and ribbon products to fulfill stringent water-blocking standards without any gels whatsoever. This dramatically decreases the cable prep time when splicing for both product families. However, the standard form of ribbon cables signifies that the advantages of all-dry technology yield much more substantial reductions in cable prep time.
Even for low fiber count applications, ribbon cables possess a significant advantage in splicing costs. The very best point for conversion to ribbon cables typically occurs at 96 to 144 fibers depending on the labor rates used for economic modeling. Because array of fiber counts, any incremental cost difference between ribbon and loose fiber configurations will probably be offset by savings in splicing costs and installation time. For fiber counts similar to and in excess of 144, the carrier would need a compelling reason not to deploy ribbon cables given the reduced price of splicing and incredibly comparable material costs.
Splicing costs vary tremendously depending on the local labor market. Typically, however, single-fiber fusion splicing prices are anywhere between $23 and $35 per-splice over a national level for standard outside-plant cable. For cost comparison purposes, we shall split the main difference and assume that we must pay $28 per-splice once we sub-contract or outsource single-fiber splicing. If we outsource ribbon-fiber splicing, we will think that each 12 fiber ribbon splice costs us $120. Ribbon-splicing costs also vary tremendously dependant upon the local labor market, but the $120 number might be from the high-average range.
So, in relation to those assumed splice costs, a typical loose-tube cable splice will cost us $4,032.00 at the 144 fiber count (144 single fibers x $28 per-splice) whereas the comparable ribbon cable splicing costs will probably be $1,440.00 (twelve 12-fiber ribbons x $120 per-splice). This will give us a total savings of $2,592.00 in splicing costs each and every splice location. In the event the 144 fiber ribbon cable costs the identical or lower than the comparable loose-tube cable, then a case for ribbon in that fiber count and higher will be the proverbial “no-brainer.” Whenever a ribbon cable is available that may complete the task in this scenario, there is little reason to take into account the alternative.
The situation for ribbon versus loose-tube optical cable is less compelling at lower fiber counts. For example, when using those same per-splice costs inside a 96 fiber count scenario, the ribbon cable saves us $1,728.00 at every splice location. However, the financial benefit afforded through the splicing could be offset by higher cable price. Additionally, dexkpky80 variety of splice locations may differ greatly in one application to another. Within a typical utility application, however, 96 fiber configurations represent the stage where cable costs and splicing costs have a tendency to break even if comparing ribbon to loose tube.
The economics of fiber counts notwithstanding, you can still find a couple of locations where either ribbon or loose-tube is definitely the preferred option. For example, it will require four splices to fix a 48 fiber count ribbon cable compared to 48 splices for your loose-tube equivalent. On certain critical circuits, therefore, it could be desirable to get FTTH cable production line just due to the advantages in emergency restoration. Also, ribbon cable goods are generally smaller which creates some space-saving advantages in conduit. However, some applications (fiber-to-the-home, as an illustration) require multiple cable access locations where we take out only two to eight fibers from your cable for splicing using mid-sheath access techniques. In those instances, ribbon might be viable with new “splittable” ribbon technologies, but could be less practical for some carriers than conventional loose tube. However, the gel-free technology seen in both ribbon and loose-tube is a big labor savings feature in those circumstances. Aerial self-supporting cables (ADSS) still require the application of some gels, but any utility company installing fiber optic cable in any other application must be leaving the gel-remover back in the shop. “Icky-pick” in conventional ribbon and loose-tube cables is a relic in the 90’s plus an accessory for labor hours which can be easily avoided.
To sum it up, there may be not a single network design which fits all applications, and not an individual cable that fits all network designs. However, knowing the options and knowing where they fit can significantly impact installation time, labor costs, and emergency restoration time. Every one of the alternatives are field-proven and have been popular for a long time. Utilities can leverage the advantages of these different solutions by simply remembering exactly what is available, and applying a little bit basic math to compare and contrast cable costs, splicing costs, and labor hours.