Best practices quiz: answers for question page 3

Answer page 3 (of 5)

In the questions and answers below, "transmission" refers to installations on lines >100 kV and "distribution" refers to installation on lines < 100 kV. NESC refers to the National Electrical Safety Code which governs all electric utility installations in the U.S. (and any other jurisdictions that adopt it).

You can work through the questions on all 5 pages, then look at the answers; take the questions one page at a time followed by their corresponding answer page; or hop back and forth by following the shortcuts at the end of every question or answer. Finally, if, like many people, you get sick of all the clicking, you can just go to one long page with all the questions and answers.

#21. Does your design meet all appropriate NESC standards? Was your system built as specified or were things fudged? (Shortcut back to question page 3)

If you can't answer yes to both questions, you're headed for trouble (see our litigation consulting page.)

Especially on distribution lines, it can be hard to squeeze in a fiber cable on to existing poles and still meet complex NESC requirements without replacing a pole. It's tempting for designers to either knowingly violate the code or, more commonly, specify an code-compliant installation on a pole that's impossible to actually install in the field.

Likewise, it's tempting for installers to install cable the easiest way, not necessarily the specified (and code-compliant) way.

The answer is careful planning for each pole, clear pole-by-pole instructions and attentive and careful project supervision.

#22. Have you set up a CLEC, hybrid fiber/coax CATV network or FTTH (fiber to the home) business or are you planning to? If so, did you get an outside feasibility study? If so, was it by a potential vendor? (Shortcut back to question page 3)

Moving from dark fiber leasing to setting up a CLEC (competitive local exchange company) or a cable TV operation is potentially lucrative and we have clients already doing this successfully. And taking fiber to the home is the ultimate potential home run in fiber deployment.

All of these activities, however, call for greater financial risks and investments as well as major organizational changes and expansions at your utility -- think and plan carefully before undertaking them. Get an outside feasibility study as a second opinion (and be aware of the pitfalls in picking the wrong consultant -- see our page on feasibility studies.)

#23. If you are offering CATV services, did you hire someone out of that industry? If you've set up a CLEC, have you hired someone with telco experience? (Shortcut back to question page 3)

Running a cable TV system or a competitive telephone company is sufficiently different from the power business that you need to bring in at least some good talent with strong backgrounds in the business you're entering -- yet we see utilities fail to do this. Conversely, we've seen utilities staff up a new division completely with outsiders -- yet it's important that at least some of the technical and managerial personnel have strong backgrounds in electric distribution design or construction.

#24. Do you always use sheaves at least the diameter required by the manufacturer? Do you know that diameter off the top of your head? Does someone check the crews - at every pole or tower - to make sure they're complying? (Shortcut back to question page 3)

Never use a sheave smaller than that recommended in the cable manufacturer's procedures unless you have specific approval to do so from the vendors. Big sheaves are a real hassle, so line crews will sometimes try to take shortcuts and use smaller, lighter, easier-to-rig sheaves than approved by the manufacturer. Don't do this -- we'd rather be your designer than your failure analysis consultant! Undersized sheaves damage cable internally in ways that may not be obvious from the outside. They void your cable warranty, too. (We've got a tech note on sheaves.)

We'll ask one more time -- even if you say your installers don't use undersized sheaves -- are you sure of this?

#25. Do you ever use a cluster of smaller sheaves in order to get the bend radius required of a large sheave? (Shortcut back to question page 3)

Installers may either rig their own cluster of undersized pulleys individually or use a "banana block" (also known as a "quadrant block" or "three-block"), a set of multiple small pulleys fixed in an arc. Using such methods ensures the manufacturer's minimum bend radius specification is met without having to struggle with heavy, full-sized sheaves. But it's still a bad choice -- these arrangements do maintain the correct bend radius, but they crush the cable by distributing the weight over a tiny area on each of several small sheaves.

#26. What fiber counts did you use? How did you pick those numbers? (Shortcut back to question page 3)

Choosing fiber counts on different routes involves an understanding of who'll be using your fiber; expected future internal SCADA, video, voice and data needs; whether you might go offering additional services such as fiber to the home, CLEC services or cable TV in the future; and your future wavelength management needs. Fiber counts are also tied into your decision as to whether to use premium fibers (see the earlier question on this topic.)

In theory, it's possible to use time division multiplexing (TDM) and wavelength division multiplexing (WDM) to shoehorn all your traffic and your customers' traffic onto just several fibers -- the fiber by itself has that much bandwidth. In reality, the network equipment to do that much multiplexing is expensive and it's usually much cheaper and easier to add more fiber to the cable. We have small-town customers using 288-fiber cables in some areas.

#27. Does your designer have fiber experience? If not (for instance, they may be a staking engineer or transmission engineer), who trained them on designing utility fiber installations? Does your designer have utility line design experience? If not, who trained them on designing fiber installation for utilities? (Shortcut back to question page 3)

Fiber optic networks require overlapping knowledge of both electric utility operations and fiber optics. Few people start out with both. How long have your designers been doing both?

Particularly with the recent slump in the cable TV and telephone businesses, many CATV and telco design firms have started going after the utility fiber business they ignored for many years. As a group, without getting extensive training in utility line design, they tend to produce designs on the surface that look inexpensive but rapidly go over budget as unforeseen make-ready expenses pile up. For instance, cable TV companies and telcos lash fiber cable to steel messenger wires in the communications space -- they're not allowed in the supply region. They use slightly less expensive fiber cable and hardware and much cheaper installation labor and equipment than power utilities use when installing ADSS in the supply zone.

So designers with telco and CATV backgrounds design the same way they always have, but this time the poles already have cable TV and telephone company cables on them. On many poles there's no room anymore for another lashed cable, so to meet NESC requirements the pole has to be replaced (including moving drops, transformers, etc.), driving make-ready costs through the roof. Since they have no background in working in the supply region, they avoid using ADSS in that area, even though with a little more upfront installation expense, the utility could cut pole replacements to under 2%. It usually only takes about 2 pole replacements per mile to make lashed aerial cable installations more expensive than ADSS installations.

Designers with powerline design backgrounds and no fiber experience usually don't specify the correct ADSS cable characteristics and create big sag and tension concerns for the future of the installation. ADSS has unique properties that must be understood in order to design a 40 year life span system.

#28. (Buried cable runs) Do you have a marker wire or marker balls to enable locating your cable in the future or do you rely on cable markers? (Shortcut back to question page 3)

Most utility fiber cable is installed aerially, but there are still underground runs -- usually around substations and in downtown areas. It's good to use warning signs ("Do not dig -- fiber optic cable") but they're not enough, especially since they get knocked down and sometimes moved. An all-dielectric cable has to be detectable to cable locator crews, which means either burying a tracer wire with it or using electronic marker balls.

#29. (ADSS) Do you ever use the "moving reel method of installation"? (Shortcut back to question page 3)

The moving reel method of aerial installation is typically used with messenger supported cables. First, a messenger must be installed on the aerial route using J-hooks at each structure. Then in a separate step, a truck with a spindle mounted on the rear of the truck or on a trailer is driven past each structure. As the truck drives the route, a "lashing machine" is pulled on the aerial line. The lashing machine can consist of a tie-wrap system or a wrapping system using mono-filament (fishing line) to wrap around the cable and messenger. There are a couple of complicated situations that might occur. First, the route may require the truck to oppose traffic or drive on the field side of the structure where a ditch would inhibit the path.

Secondly, the structures may be so crowded in the communication region that the operator has difficulty maneuvering the lashing machine past the structure. Thirdly, the sag requirements to match cables above and below may be so different that the new cable may clash with existing cables at installation.

The moving reel method is only acceptable when a messenger is used. The reason is that the structures are load balanced by the messenger since the ends of the route will terminate in downguys. If no messenger is used and ADSS is installed. The truck drives by a structure and attaches the cable but the truck can not balance the load on the structure since there is no backtension on the reel. This is not possible since the truck is moving and a reel brake would not be able to keep uniform pressure. The real danger is when a dead-end structure is tensioned and the first dead-end is applied. The uneven load is typically enough to bend a wood distribution pole and break power crossarms. Conductors drop and everyone is unhappy.

For these reasons, the moving reel method is never acceptable for ADSS installations.

#30. (ADSS) Do you use installation crews with cable TV or telephone fiber experience? Do you use crews with a power installation background? If they have a power background, who's trained them on installing fiber? (Shortcut back to question page 3)

Fiber optic networks require overlapping knowledge of both electric utility operations and fiber optics. Installation crews with a firm understanding of both may not be available. So which do you use -- cable TV or telecommunications installers with years of fiber cable experience but none of it in the utility's "supply" space or traditional electric line construction personnel?

The answer is simple, go with the power-qualified line construction crews (either contractors or in-house crews) and train them on the specifics of fiber. Power utility fiber construction at the worker level is 95% good, safe utility line construction methods and 5% special fiber handling considerations.

We can train a good line construction crew that's new to fiber in one day, supervise them for a few days, then turn over supervision to our client (who we also train) with confidence they'll complete the installation with no major problems.

In contrast, cable TV or telephone contractor crews just don't have the equipment or the skills to work in the supply region. It's too big an undertaking to retrain and re-equip them for utility line construction just for your fiber project.

For Fiber Planners projects, we have an approved list of good contractors we've worked with. We are also open to working with other good installers our utility client likes and has worked with. (If you want to recommend a good power line construction crew to Fiber Planners, let us know.)

Finally, it may sound like we're down on line crews after our comments about sheaves, etc. We're not -- most linemen are conscientious. They work in a hazardous field where sloppiness can get them killed or fired. In our failure analysis consulting, we find installation problems usually involve lack of proper fiber installation training, inadequate supervision and poor designs (or inadequate instructions from the designer). Personnel turnover within crews after initial training and project briefings can also cause problems; new personnel should get the same training and be watched carefully initially to make sure they know what they're doing with fiber.

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