Quick Hits

📱 EPISODE 1 — Article 342 (Part 1 of 2)

Intermediate Metal Conduit (IMC) — Scope & Uses Permitted

SLIDE 1 — What Is IMC? New Territory: Raceways!
🔧 A NEW CATEGORY — WE'RE INTO RACEWAYS NOW

Article 342 covers Intermediate Metal Conduit (IMC) — thinner-walled and lighter than Rigid Metal Conduit (RMC), but usable everywhere RMC is permitted. Threaded fittings ARE interchangeable between IMC and RMC — but threadless fittings are ONLY for the conduit type indicated on their packaging.

📋 Listing (342.2): IMC, factory elbows/couplings, and associated fittings — all listed.

♻️ Reconditioned equipment (342.3): IMC, its factory elbows/couplings, and fittings are NOT permitted to be reconditioned and installed.

SLIDE 2 — Uses Permitted (342.10)
✅ IMC IS INCREDIBLY VERSATILE

✅ ALL atmospheric conditions and occupancies (342.10(A))
✅ Corrosion environments — concrete, direct earth contact, direct burial, severe corrosive influences — WHEN protected by approved corrosion protection (like galvanized steel or PVC-coated steel)
✅ Cinder fill — IF protected by 2 in. of noncinder concrete on all sides, buried 18+ in. under the fill, OR protected by approved corrosion protection
✅ Wet locations — but supports/bolts/straps/screws must be corrosion-resistant or protected
✅ SEVERE physical damage — IMC can handle it

This is a tough, adaptable raceway.

SLIDE 3 — Dissimilar Metals & Sizing
⚠️ AVOIDING GALVANIC ACTION (342.14)

Dissimilar metals in contact should be avoided where practicable to prevent galvanic corrosion. Rules:
🔹 Stainless steel/aluminum fittings CAN be used with galvanized steel IMC (if not subject to severe corrosive influences)
🔹 STAINLESS STEEL IMC can ONLY pair with: stainless steel fittings, stainless steel boxes/enclosures, steel boxes/enclosures (galvanized/painted/coated, if not severely corrosive), stainless/nonmetallic/approved accessories, or identified bimetallic couplings

📏 SIZE LIMITS (342.20)
🔹 Minimum: trade size ½ (metric designator 16)
🔹 Maximum: trade size 6 (metric designator 155)

SLIDE 4 — Conductor Fill & Bends + Exam Question
🔢 NUMBER OF CONDUCTORS (342.22)

Conductor count is limited by the percentage fill in Chapter 9, Table 1. Cables are permitted too (where not prohibited by their own article), also subject to that same percentage fill limit.

🔄 BENDS (342.24)

• Bend radius: per Chapter 9, Table 2 — can't damage the conduit or reduce its internal diameter

• Total bends per run: max 360° between pull points — same rule you've seen across other raceway articles

🧠 TEST YOURSELF

Q: Per 342.20, what is the maximum trade size permitted for IMC?

A) Trade size 4
B) Trade size 5
C) Trade size 6
D) Trade size 8

(Drop your answer 👇)

FOLLOW — Part 2 wraps up threading, securing/supporting, couplings, and grounding ⚡ #JoshTheSparky #NEC2026 #ElectricianLife

← View Chapter 3 Home

← Back To Article 342 Home

← Back To Quick Hits Home