220-1101 Question 198
Single answerDirect burialA small business wants to extend Ethernet connectivity from its main office to a detached warehouse about 60 meters (197 feet) away across a parking area. The owner wants the cable installed underground with minimal future maintenance and asks which cabling choice is most appropriate for this outdoor run. Which should the technician recommend?
- A
Standard indoor Cat 6 UTP run through the trench because the distance is under Ethernet limits
- B
Direct-burial-rated outdoor Ethernet cable designed to be placed underground
- C
Plenum-rated Cat 6 cable because it is designed for environmental safety
- D
Standard PVC-jacket patch cable inside flexible plastic tubing intended for temporary outdoor use
Show answer and explanation
Correct answer: B
Explanation
For an underground outdoor network link, the key issue is not just Ethernet distance but environmental suitability. CompTIA A+ objectives expect technicians to recognize cable types by installation environment. Direct-burial cable is intended for placement underground and is built to withstand moisture and soil exposure better than indoor-rated cable. Plenum rating addresses fire and smoke characteristics for indoor air spaces, not underground use. Likewise, ordinary patch cable is meant for short, accessible device connections, not permanent buried infrastructure. In real deployments, technicians should also follow local building codes, manufacturer installation requirements, and best practices such as proper trench depth, surge protection where applicable, and considering fiber in environments with electrical grounding concerns between buildings.
- A. Incorrect.
Incorrect. Although 60 meters is within the 100-meter Ethernet distance limit for twisted-pair copper, standard indoor Cat 6 UTP is not designed for underground exposure. Moisture, soil contact, temperature changes, and physical stress can quickly degrade indoor cable jackets and conductors.
- B. Correct.
Correct. Direct-burial-rated outdoor Ethernet cable is specifically manufactured for underground installation. Its jacket and construction are designed to resist moisture, soil contamination, and environmental damage, making it the proper recommendation for an underground outdoor run where low maintenance is a priority.
- C. Incorrect.
Incorrect. Plenum-rated cable is intended for installation in plenum spaces, such as air-handling areas in buildings, where low-smoke and fire-resistance characteristics are required. It is not the same as direct-burial cable and is not chosen for underground soil contact.
- D. Incorrect.
Incorrect. A standard patch cable, even if placed in flexible tubing, is not the proper long-term solution for underground installation. Temporary tubing may not provide the sealing, crush protection, or environmental resistance required, and patch cables are not intended for permanent structured cabling runs.