Quick Hits

📱 EPISODE — Article 340

Underground Feeder and Branch-Circuit Cable: Type UF

SLIDE 1 — What Is Type UF Cable?
🌍 THE DIRECT-BURIAL COUSIN OF NM

Type UF cable is designed for UNDERGROUND feeder and branch-circuit use — including direct burial in the earth. Think of it as NM cable's tougher, moisture-resistant sibling built specifically for going in the ground.

📋 Listing (340.2): the cable itself, PLUS ties/staples/straps/hangers, AND connecting fittings.

SLIDE 2 — Uses Permitted (340.10)
✅ WHERE UF CABLE CAN GO

✅ Underground, INCLUDING direct burial
✅ As SINGLE-conductor cables — but if used this way, ALL conductors (grounded + EGC included) must be installed per 300.5
✅ Wet, dry, OR corrosive locations
✅ Installed AS nonmetallic-sheathed cable — must comply with Article 334 Parts II and III (EXCEPT 334.12(A)), and must be MULTICONDUCTOR type
✅ As single-conductor NONHEATING leads for heating cables (per 424.43)
✅ Supported by cable trays — MUST be multiconductor type when used this way

📌 UF is versatile — it can function like NM cable above ground too, as long as it follows NM's installation rules.

SLIDE 3 — Uses NOT Permitted (340.12)
🚫 A LONG LIST — SAME FAMILY AS NM'S RESTRICTIONS

❌ AS service-entrance cable
❌ Commercial garages
❌ Theaters and similar locations
❌ Motion picture studios
❌ Storage battery rooms
❌ Hoistways, elevators, escalators
❌ Hazardous (classified) locations (unless another article specifically permits)
❌ Embedded in poured cement/concrete/aggregate (EXCEPT embedded in plaster as nonheating leads per 424.43)
❌ Exposed to direct sunlight, UNLESS identified as "Sunlight Resistant"
❌ Subject to physical damage
❌ As overhead cable, EXCEPT as messenger-supported wiring per Article 396 Part II

⚠️ Important note: the sunlight-resistant marking on the JACKET does NOT apply to the individual conductors inside — this matters if the jacket is stripped back.

SLIDE 4 — Bending Radius, Ampacity & Construction + Exam Question
📐 BENDING RADIUS (340.24)
Same formula as NM/SE cable: 5x the cable diameter. Flat cables use the MINOR diameter for flat-side bends, MAJOR diameter for all others.

📊 AMPACITY (340.80)
Capped at 60°C (140°F) conductor ampacity per 310.14 — no exceptions listed here, unlike SE cable's conditional 60°C rule.

🏗️ CONSTRUCTION SPECS
🔹 Conductors (340.104): 16 AWG–4/0 AWG copper, 14 AWG–4/0 AWG copper-clad aluminum, 12 AWG–4/0 AWG aluminum
🔹 EGC (340.108): permitted to include an insulated OR bare EGC in addition to insulated conductors
🔹 Insulation (340.112): moisture-resistant type per Table 310.4(1) or identified for UF use. If used as an NM substitute → insulation must be rated 90°C
🔹 Sheath (340.116): flame retardant; moisture, fungus, AND corrosion resistant; suitable for direct burial

🎉 That wraps up Article 340 — Type UF Cable!

🧠 TEST YOURSELF

Q: Per 340.80, the ampacity of Type UF cable is based on conductors rated at what temperature?

A) 60°C (140°F)
B) 75°C (167°F)
C) 90°C (194°F)
D) Whatever temperature the conductor insulation is rated for, with no cap

(Drop your answer 👇)

Article 340 = DONE ✅ FOLLOW for more daily quick-hit NEC study notes ⚡ #JoshTheSparky #NEC2026 #ElectricianLife

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