Quick Hits

📱 EPISODE 1 — Article 338 (Part 1 of 2)

Types SE and USE Cable — Scope & Uses Permitted

SLIDE 1 — What Is SE/USE Cable?
🔌 SERVICE-ENTRANCE CABLE BASICS

Two main types, different purposes:
🔹 Type SE — suitable for ABOVEGROUND installs; both conductors AND outer jacket are sunlight-resistant
🔹 Type USE / USE-2 — suitable for UNDERGROUND installs (including direct burial); sunlight-resistant too, but NOT suitable inside premises or aboveground (except terminating at service/metering equipment)

📌 There's also submersible water pump cable — a multiconductor assembly of 2-4 single-conductor USE/USE-2 cables, tag-marked for use within a well casing for deep-well pumps.

Temperature note: if the cable surface ISN'T marked with a conductor type, the DEFAULT temperature rating is 75°C.

📋 Listing (338.2): the cable itself, PLUS ties/staples/straps/hangers, AND connecting fittings.

SLIDE 2 — Use as Service-Entrance Conductors (338.10(A))
🔌 THE PRIMARY USE CASE

SE cable IS permitted as service-entrance conductors — installed per 230.6, 230.7, and Article 230 Parts II, III, and IV. This is the classic application: running SE cable from the utility connection to the meter/panel.

SLIDE 3 — Use as Branch Circuits or Feeders (338.10(B))
⚡ SE CABLE BEYOND THE SERVICE

Type SE CAN be used for branch circuits/feeders IF:
✅ ALL circuit conductors are thermoset or thermoplastic type (338.10(B)(1))
✅ Insulated conductors handle circuit wiring; the UNINSULATED conductor is used ONLY for equipment grounding (338.10(B)(2))

⚠️ Exception: existing installations CAN use an uninsulated conductor as the GROUNDED conductor (per 250.32/250.140) — but this is grandfathered, NOT for new work. New branch circuits to ranges/ovens/cooktops/dryers can't use a bare-neutral SE cable.

🌡️ Temperature limitations (338.10(B)(3)): can't exceed the temp rating specified for that insulation type when supplying appliances.

SLIDE 4 — Installation Methods + Exam Question
🏠 INTERIOR vs. EXTERIOR INSTALLS (338.10(B)(4))

Interior: follows Article 334 Part II rules (EXCLUDING 334.80). Key ampacity nuance: SE cable with ungrounded conductors 10 AWG and smaller, installed in contact with thermal insulation, is limited to 60°C ampacity — but ONLY under that specific condition (unlike NM cable, which is ALWAYS capped at 60°C).

Exterior: follows Article 225 Part I, supported per 334.30. Type USE installed as underground feeder/branch circuit cable follows Article 340 Part II — EXCEPT single-conductor USE and multi-rated USE conductors aren't subject to 340's ampacity limits.

🧠 TEST YOURSELF

Q: Per 338.10(B)(4)(a)(3), Type SE cable with ungrounded conductors 10 AWG or smaller, installed in contact with thermal insulation, is limited to what ampacity rating?

A) 60°C
B) 75°C
C) 90°C
D) No limitation applies

(Drop your answer 👇)

FOLLOW — Part 2 wraps up uses not permitted, bending radius, and construction specs ⚡ #JoshTheSparky #NEC2026 #ElectricianLife

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