Quick Hits

📱 EPISODE 1 — Article 370 (Part 1 of 2)

Cablebus — Scope & Uses

SLIDE 1 — What Is Cablebus?
🔌 A FRAMEWORK, NOT AN ENCLOSED RACEWAY

Cablebus is a metal structure/framework (similar to cable tray) where continuous runs of insulated conductors (1/0 AWG+) are field-installed on special insulating blocks at controlled spacing intervals. A ventilated top cover fully encloses the conductors.

♻️ Reconditioned equipment (370.3): cablebus and fittings NOT permitted to be reconditioned and installed.

SLIDE 2 — Uses Permitted & NOT Permitted
✅ USES PERMITTED (370.10)

✅ Any voltage/current for spaced conductors — EXPOSED work only (except per 370.18)
✅ Branch circuits, feeders, AND services
✅ Indoors, outdoors, or corrosive/wet/damp locations — WHERE identified for the use

🚫 USES NOT PERMITTED (370.12)
❌ Hoistways
❌ Hazardous (classified) locations (unless Chapter 5 specifically permits)

📍 INSTALLATION (370.18): cablebus CAN extend transversely through partitions/walls, or vertically through platforms/floors, in wet or dry locations — installed per 300.23.

SLIDE 3 — Conductor Requirements & Termination
⚡ CONDUCTORS (370.20(A))

🔹 Insulation rating: 75°C (167°F) or higher, approved type
🔹 Minimum size: 1/0 AWG (never smaller, regardless of design)

🔌 TERMINATION (370.20(B)): approved terminating means required.

📌 Key nuance: free air circulation around conductors in cablebus means AMPACITY can be pulled from "free air" tables — but terminations at supply/load-end equipment are still limited by standard Table 310.16 (60°C/75°C) or Table 315.60(C)(3)/(C)(4) (90°C) ampacities. This can require larger/parallel conductors at the transition points.

SLIDE 4 — Overcurrent & Support + Exam Question
⚡ OVERCURRENT PROTECTION (370.23)

Protected per cablebus conductor ampacity, per 240.4 (Exception: 245.26/245.27 for medium/high-voltage systems).

🛠️ SUPPORT (370.30(A)): securely supported at intervals not exceeding 12 ft (3.7m) — longer spans need specifically designed structure.

🧠 TEST YOURSELF

Q: Per 370.20(A)(2), what is the minimum conductor size permitted in a cablebus system?

A) 2 AWG
B) 1/0 AWG
C) 4/0 AWG
D) 250 kcmil

(Drop your answer 👇)

FOLLOW — Part 2 wraps up conductor supports, fittings, and grounding ⚡ #JoshTheSparky #NEC2026 #ElectricianLife

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