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📱 EPISODE 1 — Article 348 (Part 1 of 2)

Flexible Metal Conduit (FMC) — Scope, Uses & Sizing

SLIDE 1 — What Is FMC?
🔧 THE FLEXIBLE METAL RACEWAY

Article 348 covers Flexible Metal Conduit (FMC) — the spiral-wound metal raceway you'll recognize as "Greenfield." Unlike RMC/IMC, this one's all about FLEXIBILITY.

📋 Listing (348.2): FMC AND its associated fittings — both listed.

♻️ Reconditioned equipment (348.3): FMC and its fittings are NOT permitted to be reconditioned and installed.

SLIDE 2 — Uses Permitted & NOT Permitted
✅ USES PERMITTED (348.10)
Simple and broad: exposed AND concealed locations.

🚫 USES NOT PERMITTED (348.12)
❌ Wet locations
❌ Hoistways (except as permitted in 620.21(A)(1))
❌ Storage battery rooms
❌ Hazardous (classified) locations (unless another article permits)
❌ Exposed to deteriorating materials (oil, gasoline)
❌ Underground OR embedded in poured concrete/aggregate
❌ Subject to physical damage

📌 Notice: no wet locations, no underground, no concrete embedment — FMC is strictly an indoor/protected-environment raceway.

SLIDE 3 — Sizing Rules (348.20)
📏 MINIMUM SIZE — WITH SPECIAL EXCEPTIONS

General minimum: trade size ½ — BUT trade size ⅜ is allowed for 5 specific situations:
1️⃣ Enclosing motor leads (per 430.245(B))
2️⃣ Lengths ≤6 ft for: utilization equipment, listed assemblies, or luminaire tap connections (410.117(C))
3️⃣ Manufactured wiring systems (604.100(A))
4️⃣ Hoistways (620.21(A)(1))
5️⃣ Listed assemblies connecting wired luminaire sections (410.137(C))

📏 Maximum: trade size 4

💡 Why the smaller allowance? Factory-assembled conductors under controlled conditions face less physical damage risk — that's why manufactured systems get the smaller minimum.

SLIDE 4 — Conductor Fill & Bends + Exam Question
🔢 CONDUCTOR FILL (348.22)

Standard fill: per Chapter 9, Table 1. BUT trade size ⅜ FMC has its OWN table — Table 348.22 — with specific max conductor counts by AWG size and insulation type (varies whether fittings are inside or outside the conduit).

🔄 BENDS (348.24)

• Can be made MANUALLY, no auxiliary equipment needed

• Bend radius: per Chapter 9, Table 2, "Other Bends" column

• Max 360° total bends per run between pull points

🧠 TEST YOURSELF

Q: Per 348.20(B), what is the maximum trade size permitted for FMC?

A) Trade size 2
B) Trade size 3
C) Trade size 4
D) Trade size 6

(Drop your answer 👇)

FOLLOW — Part 2 covers securing/supporting and the critical grounding rules ⚡ #JoshTheSparky #NEC2026 #ElectricianLife

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