Quick Hits

Episode 3: Fuseless vs. Fused Protectors & NIU Rules (742.10(B)–(D))

SLIDE 1 (HOOK / COVER) ⚡ NEC Quick Hit: Fuseless vs. Fused Protectors (Part 3 - Article 742) ⚡ 

Should you install a fuseless or fused primary protector? Where should network interface units (NIUs) be grounded? Let's break down Section 742.10(B)–(D)! 👇

SLIDE 2 (FUSELESS vs. FUSED PROTECTORS)

Selecting the Right Protector Type:

• Fuseless Protectors Permitted: When cables enter buildings via effectively grounded metallic sheaths that safely fuse under fault currents exceeding the protector/bonding conductor capacity.

• Fused Protectors Required: If fuseless criteria are not met, fused-type primary protectors must be used (consisting of an arrester connected line-to-ground and a series line fuse).

SLIDE 3 (NETWORK INTERFACE UNITS - NIU)

Broadband & NIU Location Rules:

• The primary protector must be installed external to or as an integral listed component inside the NIU.

• Point of Entrance: Primary protectors must be located as close as practicable to the point of entrance to ensure the shortest possible grounding electrode conductor!

SLIDE 4 (WRAP-UP)

💡 Apprentice Pro-Tip: Keeping primary protector grounding leads as short and straight as possible minimizes high-frequency inductive impedance during a lightning strike, safely shedding surges directly into the earth!

💬 Save this post for your next service entrance or broadband audit! 🔗 

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