THE SHORT ANSWER
LCEC says inverter-based gross power rating normally uses total installed AC inverter capacity; if total DC capacity is lower than inverter AC capacity, it uses total DC capacity multiplied by 0.85. [1]
Inventory both sides of the system
List every module and inverter or microinverter model with quantity and nameplate capacity. Do not substitute annual kWh production for kW capacity. Save the manufacturer sheets used so a reviewer can reproduce the inputs.
Apply the conditional rule
Compare total installed DC capacity with total installed inverter AC capacity first. The LCEC form describes a special calculation only when the DC total is lower. Ask the designer to state which branch applies and show the arithmetic.
Check the tier boundary
LCEC’s form separates Tier 1, Tier 2 and Tier 3 by gross power rating. A small equipment revision near a boundary can change fees, insurance and review requirements. Recalculate before approving a substitution or expansion.
Keep documents synchronized
The application, one-line, module schedule, inverter schedule and permit set should show the same quantities. If one document reports a different rating, correct the source rather than explaining the discrepancy in a loose note.
Preserve the approved calculation
Store the dated worksheet and cut sheets with LCEC’s response. For a future repair, expansion or home sale, this shows what the utility reviewed and prevents a service technician from treating the marketing system size as the approved gross rating.
Before your next conversation
- Total DC module nameplates.
- Total AC inverter nameplates.
- Show which LCEC calculation applies.
- Recheck the tier after substitutions.
Primary sources
- LCEC: Customer-Owned Renewable Generation Application and Compliance Form
Primary reference checked September 9, 2026. Confirm the current form, tariff, account process and equipment instructions for your address and system.
Planning examples and questions are Origin’s editorial guidance, not a property-specific diagnosis, engineering design, tax determination or promise of savings. Manufacturer and utility references do not imply an affiliation with Origin.
Make the decision specific to your home.
Use Origin Direct to verify the LCEC gross-rating method before the application is signed.
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