Optical fiber cables with metallic components must be properly bonded and grounded, while fully dielectric cables do not require electrical grounding.

Key Principles

Optical fiber cables transmit data as light, so the fiber core itself is non-conductive and does not carry electrical current. Fully dielectric fiber cables, which contain no metallic elements, do not require grounding. However, many fiber optic cables include metallic components such as steel armor, copper strength members, aluminum moisture barriers, or metallic messenger wires. These components must be grounded to prevent electric shock, equipment damage, fire hazards, and to dissipate electrostatic charges that may accumulate on the cable or surrounding structures .

Standards and Codes

Grounding practices are guided by the National Electrical Code (NEC) Article 770, NFPA 70, and additional industry standards from IEEE, TIA, and ANSI. NEC Article 770.93 specifically addresses grounding or interruption of non-current-carrying metallic members of optical fiber cables, requiring grounding at building entry points or termination locations when metallic elements are present . Local codes may also impose additional requirements.

Practical Grounding Steps

1. Identify metallic components: Check the cable datasheet or jacket markings to confirm the presence of armor, metallic strength members, or foil layers .
2. Prepare the bonding surface: Strip back 6–8 inches of the outer jacket and clean the metallic surface to remove oxidation or coatings for low-resistance contact .
3. Attach a bonding clamp: Use a UL-listed cable bonding clamp or manufacturer-supplied grounding kit to secure the metallic component .
4. Connect the grounding conductor: Run a copper grounding wire (minimum 14 AWG or as specified by local code) from the clamp to the nearest grounding electrode or equipment grounding bus, keeping the path short and direct .
5. Bond at both ends: For long cable runs, ground metallic components at each building entry point and termination to prevent induced voltages from lightning or power-line faults .
6. Verify continuity: Ensure a low-resistance path exists between the metallic components and the grounding system.

Special Cases

• Armored fiber cables: Require grounding due to their conductive armor. Dielectric-armored cables are available, which provide mechanical protection without the need for grounding .
• Optical Ground Wire (OPGW): Used in overhead power lines, combining grounding and fiber optic communication. The metallic layers bond towers to earth ground and shield high-voltage conductors from lightning, while the optical fibers provide data transmission .

Summary

• Dielectric fiber cables: No grounding required.
• Metallic or armored fiber cables: Must be bonded and grounded according to NEC and industry standards.
• Conduits or trays carrying metallic fiber cables: Must also be grounded.
• Proper grounding ensures safety, equipment protection, and reliable network operation . Following these guidelines ensures compliance with electrical codes and protects both personnel and equipment from electrical hazards.