Preventing Insertion Loss in Category 6 Cables
Copper high-performance cabling (voice and data) is routinely tested for insertion loss (attenuation) after installation. Nearly 20 years ago a contributing factor in signal degradation was identified: cable pulling lubricants create a conductive coating over the cable jackets, allowing electrons to migrate and causing insertion loss. This discovery was dubbed the “wet link phenomenon”. In 2006, Polywater®, a leading cable pulling lubricant manufacturer, studied the matter and in January 2007 released a white paper published by the Telecommunications Industry Association (TIA). The study confirmed that: 1) the mere presence of water-based lubricant outside a cable formed a conductive field leading to insertion loss; 2) that the effect was transitory and disappeared once the lubricant evaporated; and 3) that the effect could be mitigated with the use of a new “thin-film technology” lubricant developed by Polywater as a result of their research.
In this Q&A, The Transmission sits down with Jake Jonnes, General Manager of Polywater’s Communications Division to explore the relevancy of this groundbreaking research paper in today’s market.
Q. Is the TIA paper we’re discussing today still available on the Polywater website?
A. Yes, I’ll make sure to provide a link for you and the readers. (See Related Resources. –Ed.)
Q. The research is now fifteen years old. Why does it still matter today?
A. With the addition to PoE, DAS, and BAS cable, we are installing more copper cables than ever before, so the problem is more critical now. Today’s high-performance cables are more susceptible to attenuation if pulled with the wrong lubricant. The need for bandwidth has grown exponentially. They’re building data centers faster than ever. The need for a specialty lubricant that solves the problem is as great as ever.
Installers need to be aware of the phenomenon and how to fix it. Qualification as a certified technician comes with a huge assumption: that you’re going to exercise great caution while installing the cable so that it performs the way the cable was designed. Any deviance from this will cause frustration for the end user and the cable technician. The expectation is that the technician won’t pull on it too hard, rub it against hard edges, exceed the bend radius, or put the wrong lubricant on it. That’s why this paper matters even more today: don’t put anything on the cable that hasn’t been laboratory tested for potential effects. Don’t put soap on the cable!
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Q. There hasn’t been a technological change in cables over time that addresses the effect?
A. No, not for this specific issue. The paper acknowledges that the effect varies by cable brand. But lubricant is the cause, which is resolved with the right lubricant choice, regardless of cable brand. The onus fell on the lube manufacturers, not the cable manufacturers.
I’d make a broader point, though, that the cable market is very dynamic and there have been tremendous technological advances. New jackets are developed all the time, and each new introduction has to be tested for performance with existing lubricants. Lubricant manufacturers must continually adapt their product offerings to the changing marketplace.
This research serves as a great example of what responsible lubricant manufacturers must do. I feel that Polywater has long been at the forefront of this. We have great relationships with many cable manufacturers. They often seek us out for testing before releasing new products to the market—and wisely so. Everyone recognizes that, like all products, there are differences by cable manufacturer, from high end to low end. We view our role as trying to make all the cable products look as good as possible.
As this paper shows, a new specialty lubricant is sometimes required for a new specialty cable because current off-the-shelf versions won’t suffice. Cable manufacturers need a working partner in the lubricant business, because if they introduce a new jacket and no existing lubricant is viable and no one is willing or able to create a new one, that new cable technology may fail in the marketplace. We have a symbiotic business relationship with cable manufacturers. We need each other.
Q. Is testing for insertion loss in data cables now a routine part of product development for cable pulling lubricant manufacturers?
A. It certainly is for us, but perhaps exclusively so. It’s definitely a buyer-beware situation.
Q. How did Polywater become aware of this attenuation problem? Did your folks discover the so-called wet link phenomenon?
A. We did not discover it. In fact, we were unaware of it until Fluke approached us, looking for help in the matter. The problem became apparent during a construction boom in Las Vegas, one of the cities that requires cabling in conduits rather than tray. When these copper network cables started failing insertion loss tests, others rightly suspected a connection with the pulling lubricant and coined the wet link terminology. We then worked closely with Fluke and numerous cable manufacturers to confirm the problem, which subsequently led to the development of a viable solution, which today is Polywater® FTTx thin-film lubricant.
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Q. Why did Fluke approach Polywater and not other lubricant manufacturers?
A: The others simply aren’t equipped to handle these questions. They don’t have the test equipment or the scientific chops. Fluke may have approached others before us. We don’t know that, but if they did, the answers obviously weren’t satisfactory.
Q. Are there any code enforcement or industry testing requirements, such as TIA or BICSI, that have come about as a result of the research?
A. Not that I’m aware of. It’s not so much a question of meeting a code as it is guidance for best practices. It’s standard practice to test for insertion loss after cable installation. It has to meet the ANSI/TIA installation standards and customer specifications. Can I put this much voltage through it? Do I have signal loss? A cabling system has to be functional for sign-off on a project. You can get attenuation from all kinds of cable mishandling. If an installer doesn’t understand the phenomenon and uses the wrong lubricant, they can be in for some confusing and costly delays as they try to troubleshoot the cause.
Q. But the research indicates that the insertion loss effect is transitory. If it self-corrects over time with evaporation of the lubricant, is it a real-world problem, or just a theoretical one?
A. Oh no, it’s a very real thing. It happens, and it’s a problem. When a cable fails an insertion loss test, there isn’t an indicator that pops up and says, “Warning. Failure due to wet link phenomenon. Retest after lubricant is dry.” A contractor who doesn’t know about the effect will be stumped as to what’s happening. Even one who’s aware and realizes, “Darn it, I used the wrong lube,” they have no way of knowing how long the effect will last. They can’t predict when the conduit will be dry, nor can they speed up the evaporation, unless they manage to force air through the duct.
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Q. So the effect isn’t about permanently damaging the cable? The related costs are essentially in time delay?
A. Sure, time is money. Unless the conduit is a closed system with airtight duct seals, the lubricant will eventually dry out and the loss disappears. There is no cable damage. This is not a compatibility issue. But what’s happening in the meantime? The system is down, and the contractor is retesting and fumbling for a solution—and not getting paid. Whether that’s a day or a week, nobody wants that situation—particularly when it’s completely avoidable. This is a simple case of knowledge and best practices saving a major headache.
Q. Does the method of cable installation or the type of data cable matter?
A. For cable type it’s really about the newer generation, such as Cat 6 and beyond. Lubricant may affect Cat 5e, for example, but it wasn’t until they started pushing the higher data speeds and performing at higher frequencies that lubricants began triggering noticeable failure.
As for the method, it doesn’t matter whether the cable is installed by hand or mechanically—as long as they don’t exceed pulling tensions—or what type of conduit or innerduct it’s pulled into, including fabric-style ducts such as Maxcell®. What matters is whether lubricant is used, and if so, which lubricant.
Obviously, there’s no loss effect if the cable is pushed or pulled dry, but that’s a huge mistake for anything other than a very short run. Each cable has a maximum pulling tension. Lubricant is essential for protecting those cables. We’ve known that for fifty years. If you’re going to spend the money on expensive cable, the least expensive part of the entire job is the lubricant that protects the asset. It’s the cheapest insurance policy you can get. Pulling dry not only risks much more difficult—if not impossible—pulls; it risks damaging the cable jacket. That’s where most cable damage occurs, during installation due to excessive pulling tension. There’s nothing that can increase your chances of successfully and safely pulling in a cable more than adding a lubricant. I’d add for clarification that we’re talking exclusively about cable in conduit here, not in tray or plenum. Lubricant is generally not needed or used for that.
Q. Does the thin-film lubricant that solves the insertion loss problem come with any trade-offs?
A. Definitely not. It’s actually one of the best lubricants available for almost any type of cable pulling or pushing application—other than cable blowing; there are specialized lubricants available specific to that. The thin-film lube offers top-notch friction reduction and compatibility. It’s an economical choice because so much less lubricant is used. It applies easily, and it’s less messy. A lot of this cable is installed in overhead pathways in premise situations where you don’t want drippy lube slopping on the carpet or onto a new hard-surface floor where people can walk by and slip on it. You don’t want a lube that stains clothes or drywall. Thin-film lube avoids all that. So, it’s an all-around excellent choice whether it’s outside plant or premise cable, big cable or small, high fiber count bundles, copper voice or data cable, or fiber to the home. It’s like the one lube that could rule them all, yet our sales remain limited to this narrow market segment—which is fine. The point is that when you use thin-film technology, there is no sacrifice in terms of performance or suitability.
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Q. Do you have any final thoughts on the paper or thin-film lubricant technology?
A. I think both are examples of our laboratory’s sweet spot. This is our game: focusing on all the scientific aspects of cable lubrication. High-performance cable is actually a small segment of our pulling lubricant market, so there was never a huge financial incentive for us to conduct the research and develop a relatively low-sales-volume product. But our scientists love solving a generic problem like this for the industry, and in this case, we did it.
Each of our lubes is tested for compatibility and performance and is developed to address a very targeted niche—often based on a cable type, because each presents a unique set of challenges. We’re very passionate about the science affecting our markets, and this attracts others seeking solutions. We encourage cable manufacturers, engineers, or really anyone experiencing a cable pulling problem to contact us. We’re happy to at least talk through a situation. Sometimes we can make a product or application recommendation that solves a problem right away for one customer. Other times it leads to an entirely new branch of scientific inquiry that results in technical papers and new products that advance the entire industry. I’m very proud of the contributions our lab crew has made over the decades.