Quick Hits
Quick Hits
Embedded Files
EPISODE 7 — Disconnecting Means General Location and Type (267.31(A)–(C))
EPISODE 7 — Disconnecting Means General Location and Type (267.31(A)–(C))
Slide 1 — Hook "The disconnecting means section is huge — splitting it into two episodes. Today: the basics of where it goes and what it has to do."
Slide 2 — 267.31(A) & (B) General & Location
A means must be provided to disconnect ALL ungrounded conductors that supply OR pass through the building/structure.
Location: inside or outside the building, or where the conductors pass through it — readily accessible, nearest the point of entrance. If not readily accessible, it must be operable by mechanical linkage from a readily accessible point (or remote electrical control for multibuilding industrial sites under single management).
Exceptions mirror the Services article: documented-switching-procedure sites, electrolytic cell buildings (685.1), lighting-standard poles/towers, and sign-support poles all get location flexibility.
Slide 3 — 267.31(C) Type
Must simultaneously disconnect all ungrounded conductors it controls, with a fault-closing rating ≥ available fault current at its terminals (fuse characteristics can contribute to that rating).
If it lacks visible break contacts, an isolating switch is required (more on that next episode).
Exception: fused cutouts can skip simultaneous disconnection IF there's a way to disconnect the load first — with a required "DISCONNECT LOAD BEFORE OPENING CUTOUTS" sign.
Exception: documented-switching-procedure sites can use single-pole units (one per phase) instead.
Slide 4 — Quiz + CTA Q: "A building/structure disconnecting means must be capable of disconnecting what?" A) Only the grounded conductor B) All ungrounded conductors that supply or pass through the building C) Only conductors originating on-site D) Nothing specific — any disconnect qualifies
✅ Answer: B — 267.31(A): all ungrounded conductors supplying OR passing through the building.
CTA: Follow for more daily quick-hit study notes 📚⚡
⚠️ 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.
Page updated
Google Sites
Report abuse