Feeders: Sizing (215), Overcurrent Protection, Taps (240.21), and Outside Feeders to Other Buildings (225)
A feeder runs from the service equipment (or the source of a separately derived system) to the final branch-circuit overcurrent device. Texas gives Feeders its own subject area on every exam (3–7 items), and the Calculations portion asks feeder load and conductor sizing directly. 2026 note: Article 215 was reorganised — the conductor-sizing rule that was 215.2 is now 215.4.
NFPA 70 National Electrical Code, 2026 edition · Reviewed 2026-09-19
A feeder runs from the service equipment (or the source of a separately derived system) to the final branch-circuit overcurrent device. Texas gives Feeders its own subject area on every exam (3–7 items), and the Calculations portion asks feeder load and conductor sizing directly. 2026 note: Article 215 was reorganised — the conductor-sizing rule that was 215.2 is now 215.4.
1. Sizing the feeder conductors — 215.4
(A) Ampacity ≥ the larger of:
- noncontinuous load + 125% of the continuous load (215.4(A)(1)) — before any adjustment/correction. Exceptions: an assembly (including the feeder OCPD) listed for 100% operation; separately installed pressure connectors rated for 100% at both ends; grounded conductors not connected to an OCPD may be sized at 100% (Exc. 3).
- the maximum load after ambient correction and bundling adjustment (215.4(A)(2)).
Also 110.14(C): the termination temperature limits the usable ampacity column.
(B) Grounded conductor: never smaller than the EGC Table 250.122 would require for the feeder OCPD (so a 200 A feeder's neutral is at least 6 AWG copper even with a tiny neutral load), and larger where 120.61 requires it. (C) A feeder that carries the entire load of a service of 55 A or less must have ampacity at least equal to the service conductors.
Informational Notes: 3% feeder / 5% total voltage drop (advisory); Annex D examples.
This is where the public part ends.
The rest of this lesson, its quiz, all 3 lessons in the module and every mock exam open with the 7-day pass for $9. If you stay, it comes off lifetime.