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📱 EPISODE 1 — Article 355 (Part 1 of 2)

Reinforced Thermosetting Resin Conduit (RTRC) — Scope & Uses

SLIDE 1 — What Is RTRC?
🔧 FIBERGLASS-REINFORCED NONMETALLIC CONDUIT

RTRC is another nonmetallic conduit option, similar in many ways to PVC but with different construction (thermosetting resin, reinforced).

📋 Listing (355.2): RTRC, factory elbows, and fittings — all listed.

♻️ Reconditioned equipment (355.3): RTRC, elbows, and fittings are NOT permitted to be reconditioned and installed.

SLIDE 2 — Uses Permitted (355.10)
✅ VERY SIMILAR TO PVC'S PERMITTED LIST

✅ Concealed — walls, floors, ceilings
✅ Severe corrosive influences (per 300.8) — where specifically approved
✅ Cinder fill
✅ Wet locations (dairies, laundries, canneries) — entire system must prevent water entry; corrosion-resistant supports required
✅ Dry and damp locations (not prohibited elsewhere)
✅ EXPOSED work — but ONLY if identified for that use
✅ Underground installations (per 300.7, 305.15)
✅ Support of nonmetallic conduit bodies (same restrictions as PVC — no luminaires/equipment support, splicing devices only)
✅ Higher-temp-rated conductors CAN be used inside — as long as they don't operate above RTRC's listed temp rating

📌 Key detail: RTRC Type XW is specifically identified for areas of physical damage — similar to how PVC uses Schedule 80.

SLIDE 3 — Uses NOT Permitted (355.12)
🚫 WHERE RTRC CANNOT GO

❌ Hazardous (classified) locations (unless another article permits)
❌ Class I, Division 2 locations (except per Table 501.10(B)(1))
❌ Supporting luminaires/equipment beyond 355.10(H)
❌ Physical damage areas — UNLESS identified for that use (marked "XW"; if aboveground AND exposed to damage, marked "AG XW RTRC")
❌ Ambient temps exceeding 50°C (122°F), unless listed otherwise
❌ Theaters/similar locations (except per 518.6, 520.5)

SLIDE 4 — Sizing + Exam Question
📏 SIZE LIMITS (355.20)

Minimum: trade size ½. Maximum: trade size 6 — with the SAME exception structure seen in PVC/HDPE (no aboveground portion, backfilled per 300.7(F), avoids hazardous Class I/Zone locations, fill within Chapter 9 Table 1 limits).

🔢 Conductor fill (355.22): per Chapter 9, Table 1 — BUT note: the NEC doesn't provide internal RTRC dimensions directly. Fill calculations rely on dimensions MARKED on the conduit or manufacturer product info.

🧠 TEST YOURSELF

Q: Per 355.12(C), what marking indicates RTRC conduit is identified for use in areas subject to physical damage?

A) "PD"
B) "XW"
C) "HD"
D) "SR"

(Drop your answer 👇)

FOLLOW — Part 2 covers bends, support table, expansion fittings, and construction specs ⚡ #JoshTheSparky #NEC2026 #ElectricianLife

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