Quick Hits

📱 EPISODE 2 — Article 366 (Part 2 of 2)

Securing, Splices, Grounding & Construction — Article 366 Complete!

SLIDE 1 — Securing & Expansion
🛠️ SUPPORT INTERVALS (366.30)

Sheet metal: supported/secured throughout entire length at intervals NOT exceeding 5 ft (1.5m).
Nonmetallic: supported/secured at intervals NOT exceeding 3 ft (900mm) and at EVERY end/joint — max distance between supports never exceeds **10 ft (3m)**.

🌡️ EXPANSION FITTINGS (366.44): required where expected length change from temperature exceeds ¼ in. (6mm) — same threshold rule seen in PVC/RTRC conduit articles.

SLIDE 2 — Splices & Taps (366.56)
🔗 WITHIN-GUTTER SPLICING RULES

✅ Splices/taps permitted WITHIN gutters, IF accessible via removable covers/doors — but conductors+splices+taps can't fill more than 75% of the gutter area
✅ Bare conductor taps must leave the gutter OPPOSITE their terminal connections, avoiding contact with different-voltage uninsulated parts
✅ ALL taps must be suitably IDENTIFIED at the gutter (circuit/equipment supplied)
✅ Tap connections need overcurrent protection per 240.21

SLIDE 3 — Insulated Conductors & Grounding
📐 DEFLECTED CONDUCTORS (366.58(A))

Where conductors deflect within the gutter (ends, raceway entries, direction changes >30°), dimensions follow the ONE-WIRE-PER-TERMINAL rule in Table 312.9(A).

🔧 GUTTERS AS PULL BOXES (366.58(B)): conductors 4 AWG+ pulled through the gutter need entry spacing per 314.28(A)(1)/(2) — straight and angle pull rules.

🌎 GROUNDING (366.60): metal gutters connect to an EGC, equipment bonding jumper, OR grounded conductor per 250.92(B)(1) or 250.142.

SLIDE 4 — Construction Specs + Final Exam Question
🏗️ CONSTRUCTION (366.100)

Must ensure electrical/mechanical continuity, substantial construction, complete enclosure, corrosion protection on all surfaces. Corner joints TIGHT; fasteners spaced ≤12 in. apart. Smooth rounded bushings/shields required at entry/exit points to prevent conductor abrasion. Covers securely fastened.

⚡ Bare live part clearance: min 2 in. between different-voltage parts on the same surface (1 in. if free in air); min 1 in. from any metal surface.

🎉 That wraps up Article 366 — Auxiliary Gutters!

🧠 FINAL EXAM QUESTION FOR ARTICLE 366

Q: Per 366.56(A), conductors including splices and taps within a gutter cannot fill more than what percentage of its area?

A) 40%
B) 50%
C) 60%
D) 75%

(Drop your final answer 👇)

Article 366 = DONE ✅

← View Chapter 3 Home

← Back To Article 366 Home

← Back To Quick Hits Home