Why CableGuard™

Features & Benefits

CableGuard™ vs PVC & Wire

 

  • National Electric Code Approval
    1. Both PVC and CableGuard’s HDPE are mentioned as acceptable Materials listed in Article 347-1 of the National Electric Code.

     

  • Material Cost
    1. PVC resins used for conduit have always had a lower per pound cost than conduit grade polyethylenes used in CableGuard. This is the main factor affecting the cost differential between PVC systems and CableGuard systems.

     

  • Installation Labor Cost
    1. PVC conduit systems are very labor intensive and can take from 2 to 20 times the man hours to install than CableGuard. PVC has to be cut to length and glued, a string blown, a pull line installed, then the cable pulled. The CableGuard is pulled off the reel directly into the trench, or laid along the side of the trench and walked into the trench.

     

  • Equipment Required
    1. PVC installations require glue, elbows, offsets, couplings, fish tape or compressor for blowing line, pulling winch, and reel stands for multiple conductor pulls
    2. CableGuard requires a reel stand or trailer and a vehicle

     

  • Total Installed Cost
    1. The total installed cost is a combination of materials, equipment, and labor. On average, users of CableGuard realize an installed cost savings of 15 to 25 % plus supervisory cost.

     

  • Potential for Cable Damage
    1. With a PVC system, cables are pulled into duct. Unless all pulls are carefully monitored, some cables may have premature failure or shortened life due to over pulling or terrain damage. Many installers pre-cut the cable and drag it across the ground as it is pulled into the conduit; another opportunity for damage. With CableGuard the cables are never pulled or handled except at the termination; all abuse is taken by the tough HDPE conduit.

     

  • Ability to Withstand Low Temperatures
    1. The brittleness temperature of CableGuard resin is – 76 degrees F. CableGuard can be installed at temperatures as low as -10 degrees F. PVC has no standardized test for low temperature, but it is well known that PVC easily shatters in cold weather.

     

  • Ability to Adjust to Ground Movement and Heaving
    1. Where conduit is buried, there is always the possibility of ground movement from soils drying, change in water levels, frost heave, tree roots and minor earth tremors. Because PVC is a brittle, jointed system, it may pull apart or crack. This provides for the entry of water and silt and possibly will prevent future cable replacement. CableGuard will elongate 400% prior to pulling apart.

     

  • Ease of Cable Pulling
    1. CableGuard’s HDPE has a coefficient of friction that is 25% lower than PVC and a further 30% reduction of the system coefficient of friction is achieved by the application of silicone emulsion to the cable as it’s installed in the duct during manufacture. This combination makes cable removal in CableGuard easier than any other cable and duct system available.

     

Comparative Quality and Life of the Two Systems

 

  • HDPE is a compound, whereas PVC is a mixture thereby providing the same quality from batch to batch.
  • HDPE has a coefficient of friction 40 to 50 percent lower than PVC, which facilitates re-pulling or replacement of cable in case of cable failure or system upgrade
  • CableGuard is pre-lubricated with a microscopic thickness of Silicone Emulsion, which reduces the coefficient of friction an additional 35 to 45 percent
  • Ground shifting does not crack HDPE as it does PVC
  • Cable is always in a friendly environment
  • HDPE is much more resistant to acids, alkali, and hydrocarbons than PVC

 

Gopher Resistance

 

It is very common to find rodents in many rural areas where oil drilling and producing are done. There are two concerns when protecting cables; one is the small pocket gopher, the other is the Nutria.

Teeth of the pocket gopher continue to grow throughout their lives, which requires that they use them continuously.

Protection of the cable inside the duct depends on providing a duct with an outside diameter large enough to prevent the rodent from biting into the duct.

Various tests of rodent resistance have been done by Colorado State University.

To summarize, the most commonly found rodents are the Pocket gophers; tests from Colorado State University indicate that a duct with an outside diameter of 1 ½ inches will provide adequate protection.

In Louisiana, there is a population of Nutria, which is significantly larger in size than the Pocket gopher and requires the use of 2 inch conduit with an outside diameter of 2.37 inches.
Field experience of over 25 years in the center pivot irrigation applications strongly suggest that there are no reported long time pocket gopher penetration in duct sizes 1 ¼’ and larger.

Unlike the Pocket gopher, the Nutria is not a burrowing animal therefore is of less threat to buried cables.

Field experience proves that directly buried cables are very vulnerable to rodent attacks.

PVC duct of any size can allow gophers to enter the conduit run by gnawing at the upset of the coupling.