Solar Array Produces On Test Load But Not Exporting: Bypass vs Normal Decision Tree

Why this matters

An array that produces measurable power into a service-mode test load but fails to export to the grid is a classic split between the array (healthy), the inverter power stage (healthy), and the grid-interactive path (blocked). The fix is almost never on the DC side, and almost never the inverter hardware. Most resolved cases trace to grid quality, anti-islanding permissives, an export configuration that has reverted to zero, or a meter or interconnection contact that is open. This tree walks the right sequence so the tech does not waste time on the array and gets to the actual blocker.

Section 1: Define "not exporting" precisely

"Not exporting" can mean several things, and the diagnostic path differs for each.

• Inverter shows zero AC output and is not connected to the grid: a connect or permissive issue.
• Inverter shows AC output but the revenue meter does not show export: a meter, CT, or wiring issue.
• Inverter shows AC output but household loads are consuming everything, so net export is zero: not a fault.
• Inverter shows AC output then immediately drops, repeats: a ride-through or anti-islanding cycle.

Confirm at the inverter AC terminals with a calibrated meter before trusting any monitoring app. The customer-facing dashboard can lag, mis-attribute, or display battery flows in a way that hides actual export.

Section 2: Verify grid quality at the AC terminals

Modern inverters require grid voltage, frequency, and stability inside the IEEE 1547 ride-through band before they will export. A service-mode test load does not require any of this.

Measure at the inverter AC terminals across a 5 to 10 minute window:

• Line-to-line and line-to-neutral voltage on each phase.
• Frequency stability.
• Neutral-to-ground voltage.

Common findings:

• High service voltage near the upper IEEE 1547 trip band. Inverter connects then disconnects every few minutes.
• Weak neutral, with measurable neutral-to-ground voltage. Inverter sees this as grid instability.
• Long service drop with measurable voltage rise under inverter output, pushing the inverter past its trip band whenever it tries to export.

If any of these is the case, the fix is on the utility side or in the service drop, not the inverter.

Section 3: Check the export configuration

Export limits and grid-support profiles can curtail an otherwise healthy system to zero export without raising a fault.

Verify:

• Export limit setting. A limit of zero kW is sometimes set during commissioning for a non-export interconnection, sometimes set inadvertently by a firmware push, and sometimes left over from a temporary configuration during commissioning.
• Volt-watt and frequency-watt curves. An overly aggressive slope can ramp the inverter to zero output as soon as it connects, especially at the top of the day on a strong service.
• Grid code profile. A profile mismatch (a generic profile loaded on a system that should be on a utility-specific profile) can hold the inverter at zero export.
• Battery operating mode. A hybrid system in self-consumption with a full battery and no household load will not export unless explicitly configured to.

A configuration export from the original commissioning is the fastest reference. If unavailable, the manufacturer's portal or service tool will show the active profile.

Section 4: Check the interconnection path

The path from the inverter to the grid passes through several pieces of hardware, any of which can break export without breaking inverter operation.

Walk in order:

• AC disconnect at the inverter: closed, no fault.
• PV branch breaker at the panel: closed, no trip indicator.
• Utility-required external disconnect (where required): closed, contacts good.
• Net meter or production meter CT: correct orientation, current direction, and polarity. A reversed CT can show export as consumption or vice versa.
• Any utility-side relay or contactor (where used): closed, energized.

If the path is electrically continuous and the inverter is producing AC, current must flow somewhere. If the home loads are not consuming it, the only path is export. If the meter does not show export, the meter or its sensing is the issue.

Section 5: Anti-islanding permissive cycle

An inverter that connects, exports briefly, then disconnects in a repeating cycle is doing exactly what it is required to do: detecting a grid condition outside its ride-through band and disconnecting per IEEE 1547.

Common triggers:

• Frequency disturbances on a weak rural feeder.
• Voltage spikes from a nearby large load cycling on and off.
• A loose or undersized service neutral.
• A failed power conditioning device upstream.

The inverter is not faulted. The fix is to identify and correct the upstream condition. Capture the inverter's event log and the timestamps of the disconnect events, then correlate against utility data if available. Many utilities will pull a recorder for residential interconnection investigations.

Section 6: When to call the utility or original installer

Escalate when:

• Grid voltage at the inverter terminals is outside the configured trip band and you cannot correct it from the customer side.
• The interconnection agreement specifies a non-export configuration and the customer's expectation does not match the agreement.
• The meter is utility-owned and reads incorrectly. The customer cannot fix this; the utility must.
• The original installer set a non-standard grid code profile and you do not have authorization to change it.

A clean close on this call has the array producing as expected, the inverter exporting within the configured limits, the meter reading correctly, and the customer told plainly what the blocker was and what was changed.

References

• NEC 2023, Article 690 (Solar Photovoltaic Systems).
• NEC 2023, Article 705 (Interconnected Electric Power Production Sources).
• NEC 2023, Article 705.12 (Point of Connection).
• IEEE 1547-2018, Standard for Interconnection and Interoperability of Distributed Energy Resources with Associated Electric Power Systems Interfaces.
• UL 1741 SB (Supplement B), Inverters, Converters, Controllers and Interconnection System Equipment for Use With Distributed Energy Resources.