Hardened Ethernet cable goes underground

An application required the extension of Ethernet (IEEE 802.3u-1995) service from a home to a garage, a distance of approximately 300 ft. Wireless communication using IEEE 802.11a/b/g equipment had proved unreliable due to the buildings' construction, which comprises stucco over embedded wire mesh. In effect, the buildings' walls form Faraday cages that attenuate radiated signals. Straight-line aerial deployment of the Ethernet cable between buildings would have required installation of support poles, and simply laying the cable on the surface of the ground would expose the cable to damage from automobiles, hungry pets, and inquisitive children. At first glance, burial of the cable appeared impractical due to the presence of a large concrete surface between the buildings. However, an alternate route through an adjacent garden would avoid tunneling beneath the concrete slab but would expose the cable to environmental hazards, such as spade work and burrowing animals.

This Design Idea describes how to environmentally "harden" a Category 5 UTP (unshielded-twisted-pair) cable conforming to EIA/TIA 568B and ISO/IEC 11801:1995 that's terminated with RJ-45 connectors (ISO 8877). Without adding repeaters, a Category 5 Ethernet cable can extend to 100m, or a little more than 300 ft. In this application, the cable run comprises 100 ft of exposed cable, 100 ft of "garden-grade" protected cable, and 100 ft more of exposed cable. To apply the idea, you have to find a way to protect and handle the exposed 200 ft of cable.

Depending on your installation's requirements, you will need various numbers and lengths of the following parts: a 100-ft-long garden hose whose fittings conform to the ANSI/ASME B1.20.7-1991.75-11.5 NH thread-form standard; a 4-Gbyte SCSI disk drive, which need not be functional; a continuous, 300-ft-long Category 5 Ethernet cable terminated in RJ-45 connectors; a 120-ft-long, nylon twine; a 5-in.-long, electrical-grade, adhesive-backed tape; a 2-in.-steel, socket-head-cap, ¼-20-thread machine screw (ANSI/ASME B1.1-1989); and two bricks.

To construct the design, uncoil and stretch the garden hose as straight as possible, perhaps using a driveway as a work surface. Place a brick on each end of the hose to prevent it from curling. If you use only one length of garden hose, cut off and discard the hose fittings. Using Torx or Philips screwdrivers as appropriate, dismantle the 4-Gbyte SCSI disk drive by removing all of the screws that retain the drive's cover. If the cover resists removal, look for screws beneath labels. Remove the drive's head-positioning magnets, which can exert a strong pull on nearby ferrous objects. Use caution to avoid pinching your fingers between the magnets and the steel surfaces. Discard the remainder of the SCSI drive.

When the cable appears at the pulling end, stop for a moment. Go to the other end of the hose and wrap an inch or two of electrical tape around the cable where it's just about to enter the hose. Return to the far end of the hose and continue pulling the cable through the hose. Stop pulling when you see the electrical-tape marker. You now have a 300-ft-long Category 5 cable whose central 100 feet the garden hose protects. If you decide to protect more of the cable, repeat the process by feeding the twine through a second length of hose. Use the hoses' couplings to make a watertight joint between lengths. If you take this approach, make sure that you properly orient the hose segments before you spend too much time threading the twine through the hose.