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EPISODE 3 — Feeder Identification — Article 266 FINALE (266.12)
EPISODE 3 — Feeder Identification — Article 266 FINALE (266.12)
Slide 1 — Hook "Final episode of Article 266! Wrapping up with how feeder conductors get identified — including DC polarity marking, unique to this voltage class."
Slide 2 — Grounded conductor, EGC & multi-voltage-system ungrounded conductors
Grounded conductor (if insulated): identified per 200.7 — same as always.
Equipment grounding conductor: identified per 250.119.
If a premises has feeders from MORE than one nominal voltage system, each ungrounded conductor must be identified by phase/line AND system at every termination/connection/splice point — using color coding, marking tape, tagging, or other approved means — and that identification scheme must be documented or permanently posted at each feeder panelboard/distribution equipment.
Slide 3 — DC system polarity marking
For feeders from a DC system operating above 1500V: ungrounded conductors 4 AWG+ need polarity identification at every termination/connection/splice point (marking tape, tagging, or approved means); conductors 6 AWG or smaller follow specific color/marking rules.
Positive polarity (6 AWG or smaller): continuous red finish, a red stripe, imprinted "+"/POSITIVE/POS markings (repeated every 24 in.), or approved sleeving/shrink-tubing with those markings — on insulation that isn't green/white/gray/black.
Negative polarity (6 AWG or smaller): same idea but black finish/stripe/markings ("–"/NEGATIVE/NEG), on insulation that isn't green/white/gray/red.
Whatever method is used has to be documented or permanently posted at each feeder distribution equipment location.
Slide 4 — Quiz + CTA Q: "For a DC feeder system over 1500V, a 6 AWG or smaller POSITIVE ungrounded conductor can be identified with a continuous outer finish of what color?" A) Black B) Red C) Green D) White
✅ Answer: B — 266.12(C)(2)(a): continuous red outer finish identifies positive polarity.
CTA: 🎉 That's a wrap on ALL of Article 266 — Feeders Over 1000V! Follow for more daily quick-hit study notes as we continue through the medium-voltage articles.
⚠️ Educational NoticeQuick Hits are educational explanations based on my understanding of the NEC. Always verify requirements in the current adopted NEC, applicable local amendments, manufacturer instructions, and with the AHJ.
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