EGC for Parallel Raceways (NEC 250.122(F))
The equipment grounding conductor for each raceway of a paralleled feeder, per NEC 250.122(F).
Example
You enter
- Overcurrent device rating (A) 400
- Number of parallel raceways 2
- Conductor material copper
You get
- Egc per raceway AWG 3
- EGC in EACH raceway 2
- Divided OCPD (A) 200
- Undersized AWG 6
Checked against published worked examples from: NEC 250.122(F).
Details, formula, and sources
ScopeEach raceway of a paralleled feeder needs its OWN full-size EGC sized to the WHOLE circuit's device - the EGC is not divided among sets the way the ungrounded conductors are. A 400 A feeder in 2 raceways takes two #3 copper, not the #6 that sizing from 200 A would give. A ground fault returns through THAT raceway's EGC alone. Flags the 2026 NEC revision, which changes the answer.
Formula or tableEach parallel raceway carries a full-size EGC sized from Table 250.122 to the WHOLE circuit's overcurrent device rating; total EGC runs = number of raceways. The EGC is not divided among the parallel sets.
Source and editionNEC 250.122(F), equipment grounding conductors for conductors in parallel, by section number - the 2023-and-earlier rule; no table is reproduced here because the sizing is delegated to this catalog's existing egc-sizing model.
Free accessThe NEC is viewable free through the NFPA online access portal; 250.122 is in every adopted edition.
What governsEstimate. AHJ and licensed electrician govern. Verify against the NEC edition adopted in your jurisdiction.
API field namesocpd_A, raceway_count, material, egc_per_raceway_awg, total_egc_count, divided_ocpd_A, undersized_awg
- Full size per raceway each raceway's EGC is sized to the whole circuit's OCPD, not the divided currentNEC 250.122(F)
- Sizing delegated the Table 250.122 lookup comes from the landed egc-sizing model, not a duplicated tableinternal reuse
- Edition sensitive the 2026 NEC revision caps the EGC at the largest ungrounded conductor in the racewayNEC 250.122(F), 2026 revision