What are the required clearance distances for fiber optic cables

The National Electrical Code establishes specific minimum distances when communications cables must run near power and light circuits. This field guide covers which edition of the NESC applies in 2026, where fiber belongs on the pole, the vertical and horizontal clearances that govern the work, and how those numbers change under real field conditions. Industry standards such as ANSI/TIA-568 and ISO/IEC 11801 provide the following guidelines: Unshielded Power Cables:50 mm (2 inches) for up to 2 kVA power cables. Attenuation is the progressive loss of signal strength that occurs as light travels through the fiber. [pdf]