Quick Hits

Episode 2: Sheath Grounding & Antenna Systems (750.42 – 750.60)

SLIDE 1 (HOOK / COVER) ⚡ NEC Quick Hit: Sheath Grounding & Antennas (Part 2 - Article 750) ⚡ 

How do you properly ground metallic cable sheaths, coaxial shields, and roof antennas entering a building? Part II of Article 750 lays down the law. Let's break it down! 👇

SLIDE 2 (BUILDING ENTRANCE SHEATH GROUNDING) Protecting Cable Entries:

• Communication & Coaxial Shields: Metal sheath members and outer conductive shields of coaxial cables must be grounded or bonded as close as practicable to the point of entrance (or terminated outside).

• Alternative Interruption: Metal sheaths can alternatively be interrupted by an insulating joint or equivalent device.

SLIDE 3 (ANTENNA MASTS & LEAD-IN PROTECTORS) Mast Grounding & Rolling Spheres:

• Masts & Structures: Metal structures supporting antennas must be grounded or bonded unless the antenna falls completely within a protective zone defined by a 46 m (150 ft) radius rolling sphere.

• Lead-In Protectors: Antenna surge protectors must be connected between conductors and grounded shields using approved grounding conductors.

SLIDE 4 (WRAP-UP) 💡 Apprentice Pro-Tip: 

Placing your sheath grounding blocks and primary protectors as close as practicable to the point of building entrance dramatically shortens bonding paths and prevents dangerous potential differences during lightning strikes!

💬 Save this post for your next telecom or antenna rough-in! 🔗 

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