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EPISODE 10 — Mechanical or Electrical Continuity over 1kva & Boxes Where Required (305.22, 305.23, 305.25)
EPISODE 10 — Mechanical or Electrical Continuity over 1kva & Boxes Where Required (305.22, 305.23, 305.25)
Slide 1 — Hook "Today: why raceways can't have gaps, why conductors can't be spliced mid-raceway, and when a box is actually required at this voltage class."
Slide 2 — 305.22 & 305.23
305.22: raceways/cable armor/sheaths must be CONTINUOUS between cabinets/boxes/conduit bodies/fittings/enclosures/outlets — exception for raceways/cables entering the bottom of open-bottom equipment (switchgear, MCCs, floor/pad-mounted transformers), which don't need to be mechanically secured to that equipment.
305.23: conductors in raceways must be continuous between outlets/boxes/devices — no splice or tap WITHIN a raceway unless specifically permitted (305.28 and several wireway-type citations).
Slide 3 — 305.25 Boxes/conduit bodies/fittings — where required
Fittings/connectors only get used with the specific wiring method they're listed for.
For conduit/tubing/Type MC/Type MV cable: a box or conduit body is required at every outlet/switch/splice/junction/termination/transition/pull point — UNLESS one of 6 exceptions applies (a shorter list than Article 300's 12, since medium-voltage cable options are narrower): (A) removable-cover wiring methods (wireways, gutters, surface raceways); (B) equipment with integral junction box/compartment; (C) an identified fitting with no splices/terminations inside (accessible unless listed for concealed use); (D) direct-buried splices/taps per 305.15(D); (E) splice/switch/terminal/pull point already in an enclosure (other than surrounding fences/walls); (F) manholes/handhole enclosures except where connecting to equipment.
(G) Covers: ALL boxes/fittings/similar enclosures need suitable covers to prevent accidental contact with energized parts or physical damage.
Slide 4 — Quiz + CTA Q: "How many exceptions to the 'box required' rule does 305.25 provide, compared to Article 300's 12?" A) 3 B) 6 C) 9 D) 12, identical to Article 300
✅ Answer: B — 305.25(A)-(F): 6 exceptions, a narrower list reflecting the more limited medium-voltage wiring method options.
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⚠️ 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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