Quick Hits

EPISODE 2 — Overcurrent Protection, Feeder Diagrams & Equipment Grounding Conductor (266.5, 266.7, 266.8)

Slide 1 — Hook "Today: how feeder OCPDs get rated, when the AHJ can demand a feeder diagram, and the feeder's equipment grounding conductor requirement."

Slide 2 — 266.5 Overcurrent Protection

• Feeders get OCP per 245.26 and 245.27.

• The OCPD's rating/setting can't be less than 100% of the sum of ALL loads that will operate simultaneously — notice this is a different (simpler) standard than the "125% of continuous load" math you've seen in the low-voltage feeder article (215) — at this voltage class, it's just 100% of the simultaneous load.

Slide 3 — 266.7 & 266.8

• 266.7 Diagrams: if the AHJ requires it, a feeder diagram must be provided BEFORE installation, showing: the square footage served, total calculated load before demand factors, the demand factors used, the calculated load after demand factors, the system voltage, and conductor size/type.

• 266.8 Feeder EGC: if a feeder supplies branch circuits that need EGCs, the feeder itself must include/provide an EGC for those branch-circuit EGCs to connect to. If the feeder supplies a separate building/structure, the 250.32 requirements also apply.

Slide 4 — Quiz + CTA Q: "Under 266.5, a feeder OCPD's rating/setting must be at least what percentage of the simultaneous load?" A) 80% B) 100% C) 125% D) 150%

✅ Answer: B — 266.5: not less than 100% of the sum of all simultaneously operating loads.

CTA: Follow for more daily quick-hit study notes 📚⚡

← View Chapter 2 Home

← Back To Article 265 Home

← Back To Quick Hits Home