You are correct, the latter is generally acceptable, and in fact, preferred in this scenario. Here's why: NEC Focus on Service Equipment

The National Electrical Code (NEC) emphasizes bonding and grounding at the service equipment. Since the point of interconnection is at the meter/main pedestal, the grounding and bonding requirements are most critically addressed there.

Single Point Grounding

Ideally, you want a single, well-established grounding electrode system (GES). Adding another grounding point at the house for the array could create a ground loop and potentially introduce unwanted currents and noise.

Effectively Grounded Path

By connecting the array's equipment grounding conductor (EGC) to the grounding bus in the meter/main pedestal, you are establishing an effective ground fault current path back to the source (the utility transformer). This is crucial for the operation of overcurrent protective devices (OCPDs) like breakers or fuses in the event of a fault.

NEC 690.47 (C)

This section of the NEC covers the grounding requirements for PV systems. The connection to the service grounding electrode system at the meter/main satisfies these requirements.

However, consider these points to ensure compliance and safety



Adequate Grounding Electrode System (GES) at the Meter/Main

The meter/main pedestal's GES must be robust and compliant with NEC requirements. This typically includes a ground rod or other approved grounding electrodes. Ensure the size and configuration are appropriate for the combined load of the house and the PV array.

Proper Conductor Sizing

The EGC from the array to the meter/main must be sized appropriately based on the overcurrent protection device (OCPD) protecting the array's output circuit. Refer to NEC 250.122.

Metallic Conduit

If metallic conduit is used for the AC conductors from the array to the meter/main, the conduit must be properly bonded to both the array inverter enclosure and the meter/main enclosure.

Continuity

Ensure a continuous, low-impedance ground fault current path from the array back to the meter/main. Inspect all connections to verify they are clean, tight, and corrosion-free.

Local AHJ Authority

Always consult with the local Authority Having Jurisdiction (AHJ) before installation. They have the final say on what is acceptable in your specific area and may have additional requirements.

Engineering Review

For larger or more complex systems, it is recommended to have a qualified electrical engineer review the design to ensure compliance with all applicable codes and standards.

In Summary:

Connecting the array EGC to the GES at the meter/main, which serves the house, is acceptable and generally preferable to adding another grounding point at the house itself, provided the GES at the meter/main is adequate for the entire system and the grounding and bonding are properly installed according to the NEC and local codes. Always prioritize a single, robust grounding electrode system at the service equipment. Always get AHJ approval for your installation. Flag for review