Code Applied by the app elec.ground.equipment-conductor
Equipment grounding conductor size
The ground that rides with a feeder is sized from the breaker ahead of it, not from the phase wires, and a 200 A breaker wants a #6 copper ground.
| When | The app uses |
|---|---|
| overcurrent device rated 200 A, copper | #6 AWG |
- Source
- NEC · 250.122, Table 250.122 · read the public text
- Editions checked
- 2017 · 2020 · 2023
- Used by
- Courses
- Amendments
No state or local amendment to this rule is on file. Not on file means the model code as written — check your jurisdiction.
A model code the authority having jurisdiction adopts.
The green wire in a feeder does not carry current until something faults, and then it has to carry enough to trip the breaker ahead of it. So its size comes from that breaker's rating, not from the phase conductors: the course's 200 A feeder, four #3/0, carries a #6 copper ground.
On a bid it is its own wire row, a smaller gauge by the same footage, and a takeoff that prices the ground at the phase size overbids the feeder.
What the app does with it
The electrical course teaches it on a card (Chapter 7, Read the one-line), and check-lesson-rules holds the card's numbers to this rule. The app counts the ground you write in a line type's conductors (4 #3/0 THHN + 1 #6 G) as its own row; it does not check the size against the breaker.
Verify against your edition
Table 250.122 gives #6 copper at 200 A. When the phase conductors are upsized (for voltage drop, say), the ground goes up in proportion (250.122(B)), and aluminum has its own column. Local amendments still govern.
Settled 2026-09-27 by Claude on the owner's delegation, from the dossier's research and the model code text; not checked against a printed book or a local amendment.
Cited by section, not reprinted: the code text belongs to its publisher. Company practice is not a rule here — it lives with your pricing.