NEC 690.47 PV grounding and the grounding electrode

Grounding a PV system is really two jobs: bonding all the metal so a fault has a low-impedance path back to the source, and connecting to earth through the grounding electrode system. NEC 690.47 ties those together for PV, and it has changed enough across editions that old habits (like "every array needs its own ground rod") are often wrong today.

Two things that are easy to confuse

• The equipment grounding conductor (EGC) bonds module frames, racking, and enclosures together and back to the inverter and service. It carries fault current and trips protection.
• The grounding electrode conductor (GEC) connects the system to the grounding electrode system — the rods, Ufer, or water pipe that ties the premises to earth.

690.47 is mainly about how the PV system connects into the existing premises grounding electrode system rather than creating a separate, isolated earth connection.

The big change: no mandatory separate array electrode

Older editions and field lore pushed installers to drive a dedicated ground rod at the array. Beginning with the 2017 NEC, 690.47 was restructured so that a PV system bonded to the premises grounding electrode system generally does not require a separate array electrode. A separate, unbonded electrode can actually create problems (a difference of potential during a fault), so the current approach favors a single, bonded grounding electrode system.

Auxiliary electrodes are permitted — 690.47 still allows you to add an electrode at the array for lightning/surge considerations — but they are supplemental and must be bonded to the main system, not a standalone earth connection.

Sizing the conductors

The grounding conductors are sized by two different tables:

For the array-side EGC, work from the overcurrent device protecting the circuit and read 250.122. For the GEC back to the electrode system, use 250.66. Don't undersize either — an EGC that is too small is a very common correction.

Module and racking bonding

Every module frame and every rail must be bonded using listed means:

• WEEBs (washer-style bonding jumpers) or listed bonding clips between modules and rails.
• Listed grounding lugs where the EGC lands on the rail.
• A continuous EGC path from the farthest module back to the equipment ground.

Manufacturers list specific hardware as part of a listed grounding system; mixing incompatible parts voids the listing, which a careful reviewer will flag.

Because most modern modules and racking use integrated bonding (the mounting clamp bites through the anodized coating to bond the frame to the rail), the EGC often only needs to land once per row rather than jumpering every module by hand. Confirm the specific module and rail combination is tested together for bonding, and note the listed bonding method on the plan so the reviewer does not have to guess how continuity is achieved across the array.

What the AHJ may still want

Even though 690.47 relaxed the separate-electrode rule, local amendments vary. Some jurisdictions still request an auxiliary array electrode, and coastal or lightning-prone areas may have their own preferences. Confirm the enforced code edition and any grounding amendments with your AHJ before you finalize the plan — our permit guides by jurisdiction note grounding quirks for major AHJs, and the NEC reference hub collects the sizing tables.

OneLine Studio is a design aid, not a permitting authority. A licensed electrician or PE must review, sign and stamp the grounding design before you file or energize.

Educational reference, reviewed 2026-07. A design aid, not a substitute for a licensed electrician or PE. Confirm the enforced NEC edition and local amendments with your AHJ.