Armored fiber optic cables with metallic components must be properly bonded and grounded according to NEC, ANSI/TIA, IEEE, and NFPA standards to ensure safety and system reliability.

Key Principles

Fiber optic cables themselves transmit data as light and do not carry electrical current, so the fiber core does not require grounding. However, any metallic components—such as steel or aluminum armor, copper strength members, metallic messengers, or moisture barriers—must be grounded to prevent electric shock, equipment damage, and fire hazards (AEN 140, Leviton, Hawell Cable) .

Applicable Standards

• NEC (National Electrical Code) Article 770: Provides binding requirements for grounding and bonding fiber optic cables with metallic components .
• ANSI/TIA-607-D: Offers guidance on telecommunications grounding and bonding practices, including armored fiber cables .
• IEEE and NFPA standards: Provide additional safety and installation guidelines for metallic cable components .

Grounding Methods

1. Identify Metallic Components: Determine if the cable contains steel tape, aluminum interlocking armor, wire braid, or copper elements .
2. Expose Armor: Carefully remove the outer jacket or heat shrink to expose the metallic armor without damaging the fiber core .
3. Install Bonding Clamp: Place the bonding clamp between the armor and inner cable jacket, ensuring only the metallic armor is compressed. Secure with nuts or screws as per manufacturer instructions .
4. Connect to Ground: Bond the armor to the telecommunications grounding busbar (TGB) or main grounding busbar (TMGB) using a grounding wire of appropriate gauge, following NEC and TIA guidelines .
5. Wrap and Protect: Use insulating tape to cover the bonding clamp and exposed armor while leaving the bonding stub accessible to maintain electrical continuity .

Special Considerations

• Dielectric-armored cables: These cables have no metallic components and do not require grounding, simplifying installation .
• Indoor vs. Outdoor: Corrugated steel tape is common in outdoor cables for rodent and mechanical protection, while interlocking aluminum armor is often used indoors or in indoor/outdoor environments .
• Conduit and Trays: Any metallic conduit or tray carrying fiber optic cables must also be grounded independently of the cable itself .

Summary

Proper grounding of armored fiber optic cables is essential for safety, equipment protection, and network reliability. Follow NEC Article 770, ANSI/TIA-607-D, and manufacturer instructions to bond metallic armor to the building's grounding system. Dielectric cables do not require grounding, but all metallic components, including conduits and trays, must be bonded to prevent hazards and ensure compliance with electrical codes .