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📱 EPISODE 3 — Article 352 (Part 3 of 3)

Expansion Fittings & Construction — Article 352 Complete!

SLIDE 1 — Expansion Fittings (352.44)
🌡️ PVC MOVES WITH TEMPERATURE — A LOT

Unlike metal conduit, PVC expands/contracts significantly with temperature swings. Expansion fittings are REQUIRED where the expected length change is ¼ in. (6mm) or greater in a straight run between securely mounted items (boxes, cabinets, elbows, terminations).

📊 Per Table 352.44: a 100°F temperature change over a 100-ft run = about 4.06 inches of length change. That's a LOT — this is why expansion fittings matter for long aboveground runs.

📌 Underground installs rarely need expansion fittings — buried conduit sees more stable temperatures, so expansion/contraction isn't usually a concern.

SLIDE 2 — Bushings & Joints (352.46, 352.48)
🛡️ BUSHINGS (352.46)

Where conduit enters a box/fitting/enclosure, a bushing or adapter is required to protect wires from abrasion — UNLESS the enclosure design already provides equivalent protection. (See 300.6(G) for extra protection on 4 AWG+ conductors.)

🔗 JOINTS (352.48)
ALL joints — between conduit lengths, AND between conduit and couplings/fittings/boxes — must be made by an APPROVED method (typically solvent cement/glue for PVC).

SLIDE 3 — Construction Specifications (352.100)
🏗️ WHAT PVC CONDUIT IS MADE OF

Rigid (nonplasticized) PVC. Must be resistant to moisture and chemical atmospheres.

Aboveground use also requires: flame retardant, impact/crushing resistant, resistant to heat distortion, resistant to low temp/sunlight effects.

Underground use requires: resistant to moisture/corrosive agents, sufficient strength for handling/installation abuse. Direct burial WITHOUT concrete encasement ALSO requires the material to withstand continued loading after installation.

SLIDE 4 — Marking + Final Exam Question
🏷️ MARKING (352.120)

Each length marked at least every 10 ft (3m) per 110.21(A) — plus the material type (unless visually identifiable). Aboveground-recognized conduit needs PERMANENT markings; underground-only conduit needs markings durable enough to stay legible until installed.

Special markings can indicate characteristics like "limited smoke" or "sunlight resistant."

🎉 That's a wrap on Article 352 — Rigid PVC Conduit!

🧠 FINAL EXAM QUESTION FOR ARTICLE 352

Q: Per 352.44, expansion fittings are required where the expected length change in a straight run is what minimum amount?

A) ⅛ in. (3mm)
B) ¼ in. (6mm)
C) ½ in. (13mm)
D) 1 in. (25mm)

(Drop your final answer 👇)

Article 352 = DONE ✅ FOLLOW for more daily quick-hit NEC study notes ⚡ #JoshTheSparky #NEC2026 #ElectricianLife

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