Communications Systems
Chapter 8 Scope
Chapter 8 covers communications systems: Article 800 (general), 810 (radio and television), 820 (network-powered broadband), 830 (network-powered broadband communications), 840 (premises-powered broadband), and related articles. These rules govern cabling, grounding, bonding, and protection.
Concepts to Master
- Separation: communications cables must be separated from power conductors by specified distances unless a barrier or specific exception applies.
- Grounding and bonding: communications systems require bonding to the grounding electrode system, and the bonding conductor has sizing rules.
- Protection: primary protectors and limiters protect premises wiring from surges and lightning on incoming lines.
- Cable types: understand the difference between communications cables and power cables, and the permitted and prohibited uses of each.
Traps
- Mixing up communications grounding requirements with power grounding requirements; they share the electrode system but have distinct rules.
- Forgetting separation distances from power conductors and the exceptions that permit closer proximity.
- Assuming any cable may be used outdoors; outdoor and underground installations have specific requirements.
- Overlooking that Chapter 8 is largely independent of Chapters 1-7 except where referenced.
Worked Example
A question asks how close a communications cable may run to a power conductor. Rule of thumb: default to the required separation; only use an exception when the question states the qualifying condition (barrier, raceway, or listed separation).
Rule of Thumb
Communications wiring must be bonded to the grounding electrode system, but bonding does not mean the same conductor sizing as power grounding.