PV Equipment Grounding Conductor (NEC 690.45)
The PV-specific equipment grounding conductor per NEC 690.45.
Example
You enter
- OCPD rating (A, 0 = no OCPD) 20
- Conductors upsized for voltage drop? no
You get
- Sizing basis 20
- Required EGC (copper) 12
Checked against published worked examples from: NFPA.
Details, formula, and sources
ScopeSized from the OCPD via Table 250.122, or, where a source circuit has no overcurrent device, from an assumed device at 125% of the PV maximum circuit current per 690.9(B), 1.5625 x Isc, never smaller than 14 AWG. 690.45 waives the 250.122(B) rule, so enlarging the conductors for voltage drop does not enlarge the EGC -- the over-build the general rules cause.
Formula or tablebasis = OCPD rating > 0 ? OCPD : 1.5625 x PV Isc (1.25 x the 690.8(A) maximum current, itself 1.25 x Isc); EGC = Table 250.122 size for the basis, never smaller than 14 AWG; the 250.122(B) proportional upsize does not apply (690.45).
Source and editionThe NEC 2023 690.45 equipment grounding conductors for PV systems, with Table 250.122, by name.
Free accessThe NEC is available through NFPA's free online read-only access at nfpa.org; the 690.45 and Table 250.122 provisions are in the published code.
What governsEstimate. AHJ and licensed professional govern.
API field namesocpd_rating_a, vd_upsized, basis_current_a, egc_awg
- No-OCPD sizing where there is no overcurrent device, the EGC is sized from an assumed device rated at 125% of the PV maximum circuit current per 690.9(B), 1.5625 x Isc (690.8(A)(1))NEC 690.45
- 14 AWG minimum the PV EGC is never smaller than 14 AWG (copper)NEC 690.45
- 250.122(B) waived the voltage-drop proportional upsize does not apply to PV EGCsNEC 690.45