New Mexico Journeyman Low Voltage Special Systems (ES-3J) Practice Test 2026 - Free ES-3J Practice Questions and Study Guide

Optical fiber cables must be listed and marked when they exceed 50 feet in length due to safety and regulatory standards. This requirement ensures that longer cables meet specific performance criteria, such as fire resistance and environmental durability, which are crucial for maintaining the integrity and safety of low-voltage systems.

Optical fiber cables that are longer tend to have more significant implications for installation, including increased potential for signal loss and the need for additional protection from environmental factors. By regulating the marking and listing of these longer cables, industry standards help ensure that they are installed correctly and safely, which is essential for both performance and compliance with building codes.

While shorter cables and those within enclosures may have fewer stringent requirements, longer optical fiber cables specifically require attention to their proper listing for safety and reliability in both residential and commercial installations.