Don’t Get Burned, Get MULETAPE!

The OSP group is proud to announce the release of a new video designed to communicate the advantages of using pre-lubricated MULETAPE, rather than standard poly-rope, to install fiber optic cable. Footage for the new video was obtained during an above-ground test we conducted at the Condux training facility in Mankato, MN. Condux International is a leading manufacturer of tools and equipment used to install copper and fiber optic cable in underground conduits, and is a long-standing NEPTCO customer.

With the help of Condux Product Manager Greg Hasse, and Product Specialist Chris Butzer, approximately 1,000 feet of high-density polyethylene pipe conduit was laid on the ground in a configuration that included several 90 bends. (See Figure 1) In the first test, a Condux blower and an innerduct projectile were used to blow NEPTCO’s 1800 lb. polyester MULETAPE through the conduit. The MULETAPE was then attached to a Condux pulling eye, and fiber optic cable was pulled through the conduit at a rate of 125 feet per minute.

Next, the 3/8” poly-rope was tested, using the same equipment and identical test parameters. The results of this pull were quite dramatic, and provided conclusive evidence that using poly-rope is risky business. Just minutes into the pull, the friction caused by the elongating poly-rope caused the rope to actually burn through the plastic conduit! The sawing motion of the rope, particularly at the 90 bends, created ever-increasing, jagged grooves in the conduit. The most critical portion of the test came when the fiber optic cable reached these jagged segments of conduit. As the cable was forced through the rough edges of the frayed plastic, its jacket was scored and shredded. (See Figure 2)
Figure 2

While NEPTCO has been using its specially designed duct cut tester for years to demonstrate the problem of “burn through” in the laboratory, this above-ground test was designed to replicate typical below ground pulling conditions. While the “burn through” witnessed during the test confirmed what NEPTCO has maintained for years, the most important discovery was even more sobering.

After both pulls were complete, we examined the fiber optic cable and the records from the Condux Chart Recorder that was used to monitor each foot of the pulls. While the cable pulled with MULETAPE showed virtually no damage to the jacket or cable core, the cable pulled with poly-rope showed signs of severe wear on the jacket, and major changes to the shape and size of the core. (See Figure 3)

Cable manufacturers publish specific guidelines regarding the amount of tension that can be safely applied to fragile optical fibers during cable installation. In this case, the maximum recommended tension was 600 pounds. According to the Condux tension meter, the cable pulled with poly-rope was subjected to more than 600 lbs. of tension several times throughout the pull. (See Figure 4) The consequences of this were evident when we examined the cable more closely: the excessive stress generated by the poly-rope can cause microbending and crushed fibers, which in turn may cause the cable to fail prematurely.

This information is critical to cable manufacturers, since in the real world, all of this happens underground. Damage to the cable may not become evident until months, or even years, after it was installed, and usually the manufacturer bears the cost of repair or replacement. The OSP sales team will be using this video as a training tool, and will also have CD Rom and internet versions available.

Click here to view the video in Windows Media Player. For more information, or to order a copy of the video in VHS or CD ROM format, contact Bob Hegan