Quick Hits

Episode 2: Conductors, Disconnecting Means & Shunting (668.12 – 668.14)

SLIDE 1 (HOOK / COVER) ⚡ NEC Quick Hit: Cell Line Conductors & Shunts (Part 2 - Article 668) ⚡ 

How do you connect massive aluminum or copper busbars that carry hundreds of thousands of amperes? Can you shunt current around individual cells? Let's check out Sections 668.12 through 668.14! 👇

SLIDE 2 (CELL LINE CONDUCTOR CONSTRUCTION) Massive Busbars & Safe Temperatures:

• Conductor Material: Cell line conductors can be bare, covered, or insulated and constructed of copper, aluminum, copper-clad aluminum, or steel.

• Thermal Sizing: Cross-sectional areas must be sized so that temperature rise under maximum load and ambient conditions does not exceed the safe operating temperature of insulation or conductor supports.

• Connections: Joined securely via bolted, welded, clamped, or compression connectors.

SLIDE 3 (DISCONNECTS & SHUNTING MEANS) Isolating and Bypassing Cells:

• Multiple Power Supplies: Where more than one DC process power supply serves a cell line, a disconnecting means (including removable links or conductors) must be installed on the cell line circuit side of each supply.

• Shunting Permitted: Partial or total shunting of cell line current around one or more cells using approved conductors and switches is fully permitted.

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

Electrolytic cell line conductors are exempt from standard general-purpose wiring rules (like Articles 110, 120, and 210) because their unique massive busbar designs require specialized industrial engineering!

💬 Save this post for your next smelter or chemical plant busbar layout! 🔗 

More code breakdowns at www.JoshTheSparky.com

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