Solar Permit Glossary: Key Terms Explained

Permit & Regulatory Terms

AHJ — Authority Having Jurisdiction

The government body that has legal authority to regulate construction and electrical work in your area. For residential solar, typically your county building department (for unincorporated areas) or city building division (for incorporated municipalities). The AHJ determines which permit forms to use, reviews your plans, sets permit fees, and employs the inspectors.

Building Permit

Official authorization from your AHJ to proceed with a construction project. For solar installations, the building permit covers the structural elements (racking, roof penetrations) and often the electrical elements as well (though some jurisdictions require a separate electrical permit).

Electrical Permit

A separate permit covering the electrical work associated with a solar installation — conductor sizing, conduit installation, panel modifications, inverter installation, disconnects, and labeling. Some jurisdictions issue this as part of the building permit; others require a separate application and fee.

Plan Review

The AHJ's review of your submitted permit documents to verify code compliance before issuing the permit. Plan review checks that your proposed installation meets the applicable building, electrical, and fire codes. Plan review is typically performed by staff plan reviewers, not field inspectors.

Certificate of Completion (CC) / Certificate of Occupancy (CO)

The document issued by the AHJ after a passing final inspection, confirming the project is complete and code-compliant. This document is what your utility needs to finalize the interconnection review and issue PTO.

Interconnection Terms

Interconnection Application

The application filed with your electric utility to authorize connection of your solar system to the grid. This is separate from the building permit and is processed by your utility's distributed generation or renewable energy team.

CAL — Conditional Approval Letter

A letter from your utility confirming technical approval of your solar system design before installation. Not Permission to Operate — it's a green light to proceed with installation. Not all utilities issue a CAL; some go directly to PTO review after the final inspection.

PTO — Permission to Operate

The final authorization from your electric utility allowing your solar system to energize and export power to the grid. PTO is issued after the utility reviews the county's final inspection report and installs (or confirms) a bidirectional net meter. Do not turn on your system before receiving PTO in writing.

Net Metering

A utility billing arrangement that credits solar owners for excess power exported to the grid. Export credit rates vary by utility and state — from full retail rate (Florida, Colorado) to avoided cost (Arizona APS, California NEM 3.0). See full guide: Net Metering Explained.

Avoided Cost Rate

The rate at which a utility values excess power it doesn't have to generate itself — typically the wholesale cost of generation. Much lower than the retail rate homeowners pay to import power. Several states have moved from retail-rate net metering to avoided cost crediting for solar exports.

TDU — Transmission & Distribution Utility

In deregulated electricity markets (mainly Texas), the company that owns the poles, wires, and meter — responsible for physical interconnection. Separate from the REP (Retail Electricity Provider) that supplies your electricity.

REP — Retail Electricity Provider

In Texas's deregulated ERCOT market, the company you buy electricity from. The REP sets your solar buyback rate — which varies from $0/kWh to near-retail depending on your plan. Distinct from the TDU that handles physical interconnection.

Code Terms

NEC — National Electrical Code

The standard for safe electrical design, installation, and inspection in the U.S. Article 690 covers solar PV systems. Most jurisdictions adopt the NEC on a multi-year cycle — verify which edition your AHJ has adopted. The 2017 NEC introduced mandatory rapid shutdown requirements.

IBC — International Building Code

The model building code addressing structural requirements — including roof loads, racking attachment, and structural integrity for solar installations. Most jurisdictions have adopted the 2018 IBC with local amendments.

IFC — International Fire Code

The model fire safety code. Sections relevant to solar include the fire setback requirements (18-inch perimeter clear path, 36-inch hip-to-ridge access path) that govern how panels can be placed on residential roofs.

SLD / Single-Line Diagram

A schematic electrical diagram showing the complete solar system from panels through inverter to utility meter. The SLD is the primary technical document reviewed by both the AHJ's plan reviewer and the utility's interconnection team. Must be prepared accurately and match installed equipment exactly.

Rapid Shutdown

NEC 2017 Section 690.12 requirement that all conductors within a solar array boundary be de-energized within 30 seconds of initiating shutdown. Protects firefighters on the roof. Most modern inverters and optimizer systems are rapid shutdown compliant. The rapid shutdown initiator must be labeled and accessible.

HVHZ — High Velocity Hurricane Zone

A designation under the Florida Building Code covering Miami-Dade and Broward counties. Solar racking in the HVHZ must carry a Miami-Dade County Notice of Acceptance (NOA) or Florida Statewide Product Approval — engineering certifying the racking system meets HVHZ wind load requirements.

Financial & Incentive Terms

ITC — Investment Tax Credit

The federal residential solar tax credit, currently 30% of the total system cost (through 2032 under the Inflation Reduction Act). Applied directly to your federal income tax liability. Not a rebate — you must have sufficient tax liability to claim the full credit, or carry it forward to future years.

SREC — Solar Renewable Energy Certificate

A tradable certificate representing 1 MWh of solar-generated electricity. In states with SREC markets (New Jersey, Maryland, Massachusetts, others), solar owners earn SRECs that can be sold to utilities needing to meet renewable portfolio standards. SREC values are market-driven and vary significantly.

NOA — Notice of Acceptance

Miami-Dade County's product approval certification for building materials used in the HVHZ. Solar racking and mounting hardware must carry an NOA to be used in Miami-Dade and Broward counties. Check product approval numbers at floridabuilding.org/pr.