What type of cable twist is used for underground applications?

The correct choice is S-twist, which is specifically designed for underground applications. S-twist cables are constructed in a way that provides optimal shielding and reduces the likelihood of interference when buried beneath the ground. This twisting technique helps maintain the integrity of the cable's signal quality, especially important in environments where external factors, such as moisture or electrical noise, could impact performance.

S-twist also has mechanical advantages; the way the wires are twisted together offers superior flexibility and strength, making it better suited for installation in tight spaces often found in underground conduits. The symmetrical structure of the twisting helps distribute any mechanical stresses more evenly across the cable, leading to a more reliable performance over time.

In contrast, the other types of twists—Z-twist, F-twist, and G-twist—are used for different applications and do not provide the same level of utility for underground installations. Each twist serves specific purposes, but S-twist is the ideal choice for underground scenarios due to its design benefits that enhance durability and performance in such challenging environments.