A copper run between a gatehouse and a barn will be buried in the ground. Which cable rating belongs in that trench?
Select an answer to reveal the explanation.
Short Explanation
Because your trench is exposed to moisture and soil, you need a jacket made for burial on this underground run. Choose direct-burial cable; plenum-rated cable is for air-handling spaces, riser-rated cable is for vertical runs between floors, and twisted pairs in ordinary unshielded cable do not keep water out.
Full Explanation
Direct-burial cable is built to tolerate moisture and burial in soil, which is what a trench between the gatehouse and the barn demands. Plenum-rated cable is for air-handling spaces inside a building; an air-return rating does not make its jacket safe to bury. Riser-rated cable is for vertical runs between floors, not the specification for an underground run. Ordinary unshielded cable has an indoor jacket: twisting the pairs controls interference, but does not keep water out of a trench. Exam caveat: conduit can protect a cable, but cable in a wet conduit still has to be rated for that wet location. Do not assume indoor cable becomes burial cable because it is inside a pipe that may fill with water. Practical check: read the jacket print and confirm it says direct burial; photograph the print at the trench so the rating is on the ticket. Keep indoor patch cords out of the trench, leave a loop of slack at each end so the buried cable is not pulled tight, and check the jacket print before backfilling.