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📱 EPISODE 1 — Article 358 (Part 1 of 2)

Electrical Metallic Tubing (EMT) — Scope & Uses

SLIDE 1 — What Is EMT?
🔧 THE LIGHTWEIGHT RACEWAY STANDARD

EMT (often called "thin-wall") is one of the most widely used raceways in commercial/industrial work — lighter than RMC/IMC, unthreaded, connected with couplings and connectors instead.

📋 Listing (358.2): EMT, factory elbows, and fittings — all listed.

♻️ Reconditioned equipment (358.3): EMT, elbows, and fittings are NOT permitted to be reconditioned and installed.

SLIDE 2 — Uses Permitted (358.10(A))
✅ EXPOSED AND CONCEALED — BROAD APPLICATION

✅ In concrete, direct earth contact, direct burial (with fittings identified for that use), or severe corrosive areas (per 358.10(B))
✅ Dry, damp, AND wet locations
✅ Hazardous (classified) locations (where other articles permit)
✅ Manufactured wiring systems (604.100(A)(2))

SLIDE 3 — Corrosion Rules by Material (358.10(B)–(E))
🧪 MATERIAL-SPECIFIC CORROSION RULES

🔹 Galvanized steel & stainless steel EMT: permitted in concrete/earth/severe corrosive areas WHEN protected by approved corrosion protection
🔹 Aluminum EMT: needs SUPPLEMENTARY corrosion protection when encased in concrete OR in direct earth contact — extra requirement beyond steel/stainless

Cinder fill (358.10(C)): galvanized steel and stainless steel EMT permitted IF protected by 2 in. noncinder concrete on all sides, OR installed at least 18 in. under the fill.

Wet locations (358.10(D)): supports/bolts/straps/screws must be corrosion-resistant.

Physical damage (358.10(E)): steel and stainless steel EMT ARE permitted where subject to physical damage — notably, this does NOT extend to aluminum EMT.

SLIDE 4 — Uses NOT Permitted, Dissimilar Metals + Exam Question
🚫 USES NOT PERMITTED (358.12)

❌ Subject to SEVERE physical damage
❌ Supporting luminaires/equipment — EXCEPT conduit bodies no larger than the largest trade size of the tubing itself

⚠️ DISSIMILAR METALS (358.14): avoid where practicable. Stainless/aluminum fittings CAN pair with galvanized steel EMT; galvanized steel fittings CAN pair with aluminum EMT (when not severely corrosive). Stainless steel EMT has the SAME restrictive pairing rules seen in RMC/IMC.

🧠 TEST YOURSELF

Q: Per 358.10(E), which materials of EMT are permitted where subject to physical damage?

A) Aluminum only
B) Steel and stainless steel
C) All EMT materials equally
D) EMT is never permitted where subject to physical damage

(Drop your answer 👇)

FOLLOW — Part 2 covers sizing, bending, threading rules, securing, and grounding ⚡ #JoshTheSparky #NEC2026 #ElectricianLife

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