Solar Inspection Preparation Checklist: Pass AHJ

Last updated: November 2026

A solar inspection fails when the field work, the plans and the paperwork disagree. The inspector does not need much time to find the gap: a grounding connection that was never bonded, a placard that is missing, a conduit run that does not match the single-line diagram.

This guide is a solar inspection preparation checklist for installers and EPC crews. It covers what each inspection type checks, the electrical, structural and labeling items that cause re-inspections, how failure rates look in published data, and a printable pre-inspection list. Code values change between NEC editions, so this guide points you to the article to check instead of quoting numbers from memory.

Failure is common even with standardized checklists. The National Renewable Energy Laboratory (NREL) tracked inspection outcomes across 12 jurisdictions in 2022. Of traditional permitting projects, 24% failed at least one inspection, against 17% of SolarAPP+ projects. NREL notes that the gap may partly reflect differences between installers who do and do not use SolarAPP+, so treat it as a working hypothesis. Also see: Us Residential Solar Market Trends 2026. For United States-specific compliance details, see United States arizona/phoenix. For United States-specific compliance details, see United States california/los-angeles.

In this guide, you will learn:

• The three types of solar inspections and what each one covers
• How to prepare electrical systems so they pass on the first visit
• Structural checks that prevent the most expensive rework
• How labeling requirements change between NEC editions
• The five inspection fail points that cost installers the most money
• Documentation that every inspector expects to see on-site
• A printable checklist you can use before your next inspection

What Inspectors Actually Check: The Three Inspection Types

Solar projects in most jurisdictions require more than one inspection, and what each one covers differs by authority having jurisdiction (AHJ). Understanding the split prevents surprises and rework.

Rough-In Inspection

The rough-in inspection happens after conduit, wiring, and grounding are installed but before walls close or panels go on the roof. The inspector checks what they cannot see after completion.

Key items at rough-in:

• Conduit routing and support spacing
• Wire sizing against approved plans
• Grounding electrode conductor installation
• Junction box placement and fill
• Conductor ampacity calculations

The rough-in is where many electrical code violations get caught early. Fix them now and you avoid tearing finished work apart later. A grounding error caught at rough-in is a materials fix. The same error caught at final inspection adds a crew return trip and a re-inspection fee.

Structural Inspection

The structural inspection verifies that the roof can support the array and that penetrations are weatherproof. Some AHJs combine this with the rough-in. Others require a separate visit.

Key items at structural:

• Lag bolt depth into rafters or trusses
• Flashing quality at every penetration
• Rail attachment spacing per manufacturer spec
• Fire setback compliance against the fire code the AHJ enforces
• Roof load calculations for the specific array weight

Structural failures are among the most expensive to fix because a bad penetration can mean a roof leak, interior damage and a damaged customer relationship.

Final Inspection

The final inspection is the gate to Permission to Operate (PTO). The inspector verifies the complete system against approved plans and code.

Key items at final:

• Module placement matches approved layout
• All labels and placards are present and legible
• Rapid shutdown system functions correctly
• Grounding continuity is verified and recorded
• Disconnect locations are accessible and labeled
• Inverter settings match utility requirements
• Fire safety pathways are clear

How long the final takes depends on system size and the AHJ. An unprepared installer turns a short pass into a long failure with a return trip.

Electrical Checks: Where Most Inspections Fail

Electrical items are where plan and field most often disagree, so they get the most attention at inspection. NEC Article 690 covers solar PV systems, and the edition your AHJ has adopted decides which rules apply. Here is how to prepare.

Circuit Sizing and Conductor Ampacity

Conductor sizing is a frequent plan-review and inspection issue because several factors stack up. The sizing worksheet should show every step the adopted NEC edition requires, in the order it requires them.

Build the worksheet from these inputs:

1. The module short-circuit current (Isc) from the datasheet
2. The continuous-current factor the adopted edition applies to PV circuits
3. Temperature correction for the conductor insulation rating and the rooftop or conduit environment
4. Adjustment for the number of current-carrying conductors in a raceway
5. The terminal temperature rating of the equipment at each end

Do not size from memory or from a rule of thumb. Pull the factors from the adopted edition and keep the worksheet with the permit file, because an inspector or plan reviewer may ask to see it.

Bifacial modules add rear-side current. How the adopted NEC edition tells you to rate maximum circuit current for bifacial modules is a point to check in the code text and the module datasheet before you size conductors and overcurrent devices. Read Bifacial Solar Panel Design Guide for a design walkthrough.

Grounding and Bonding

Grounding deficiencies are a common inspection failure. NEC Article 690 and Article 250 govern bonding of module frames, rail systems, conduit, junction boxes and inverter enclosures. See the glossary entries on equipment grounding and bonding.

Inspectors may check continuity with a low-resistance meter. Use the acceptance criteria in the racking and module manufacturer’s installation instructions and the AHJ’s requirements, and record the readings. Many installers skip the test because they assume the mechanical connections are sufficient. That is a risk, especially on painted or anodized surfaces.

Common grounding failures:

• Missing bonding jumpers between rail sections
• Painted surfaces preventing metal-to-metal contact
• Corroded grounding electrode connections
• Improper grounding electrode conductor sizing
• Module frames not bonded the way the manufacturer’s instructions require

Rapid Shutdown Compliance

Rapid shutdown, covered by NEC 690.12, reduces voltage in certain PV circuits when the system is shut down. It exists to protect firefighters during emergencies. The voltage and time limits, and the boundary definitions, depend on the NEC edition the AHJ has adopted, so check the code text and the equipment’s listing instructions. See also the glossary entry on rapid shutdown.

Inspectors check three things:

1. Device placement within the rapid shutdown boundary
2. Proper labeling at the array and service disconnect
3. Functional test of the shutdown system

Common rapid shutdown failures:

• Inverter and optimizer communication incompatibility
• Missing weather-resistant placards at shutdown boundaries
• Ambiguous single-line diagrams showing shutdown perimeters
• Label placement that does not match the adopted edition’s requirements

Label locations and wording have changed between code editions. Installers working from old reference materials can place labels in the wrong locations, so read the labeling requirements entry and the edition your AHJ enforces.

Overcurrent Protection

NEC 690.9 addresses overcurrent protection for PV circuits, and the inspector checks breaker sizing, fuse ratings, and labeling.

Key requirements to check against the adopted edition:

• OCPDs marked as the code requires for PV circuits
• Backfed breaker location rules where the busbar method is used for the interconnection
• Fuse ratings that do not exceed the module maximum series fuse rating on the datasheet
• Breaker sizing that follows the continuous-current factor in the code

A backfed breaker in the wrong position on the busbar is a code violation the inspector will flag. Moving a breaker takes minutes if caught early. It takes a re-inspection if caught at final.

Voltage Calculations

NEC 690.7 addresses maximum PV system voltage, calculated from the module open-circuit voltage (Voc) with a correction for the lowest expected ambient temperature. Most designers use design software or manufacturer calculators. The inspector may ask to see the calculation.

Key points:

• Use the temperature coefficients from the module datasheet
• Use the lowest expected ambient temperature for the site
• Check the maximum system voltage allowed for the building type in the adopted edition

A string that looks fine at standard test conditions can exceed the limit on a cold morning. That is a code violation in cold climates, and it is a design error rather than an installation error.

Structural Checks: The Most Expensive Failures

Structural failures are expensive because they can damage the building and the customer relationship. A missed bond is a quick fix. A leaking penetration is a repair, a callback and a reputation problem.

Roof Penetrations and Flashing

Every roof penetration is a potential leak. The inspector checks flashing quality, sealant application, and waterproofing at every lag bolt location.

Preparation checklist for roof penetrations:

• Verify flashing matches roof material (composition, tile, metal)
• Check sealant coverage under flashing bases
• Confirm no gaps between flashing and roof surface
• Look for cracked or missing sealant at existing penetrations
• Test water runoff paths do not pool near penetrations

Lag Bolt Installation

Lag bolts must engage structural members. The inspector may ask for proof. Some AHJs require pre-installation photos showing bolt placement into rafters.

Key requirements:

• Minimum embedment depth per the racking manufacturer’s specification
• Engagement into rafter or truss, not just decking
• Proper pilot hole sizing to prevent wood splitting
• No over-torquing that strips threads

A lag bolt that misses the rafter provides no structural value. The array can lift in high winds. This is a safety failure, not just a code issue.

Fire Safety Pathways

Most jurisdictions require clear pathways for fire department access. The pathway widths and setbacks come from the fire code the AHJ has adopted and any local amendment, and they can vary with roof size and layout. Get the requirement from the AHJ or fire marshal before layout, not at inspection.

Common fire pathway failures:

• Modules placed too close to ridge lines
• Arrays that block access to roof vents or skylights
• Conduit runs that obstruct pathways
• Missing labels identifying shutdown locations

The fire department does not care about your array layout. They care about putting out a fire without getting electrocuted. Respect the pathways.

Rail Attachment Spacing

Rail attachment spacing must follow manufacturer specifications. These vary by module size, wind zone, and roof type. The inspector may measure spacing with a tape measure.

Common spacing errors:

• Attachments spaced too far apart for wind load
• End clamps placed too close to module edges
• Mid clamps missing at splice joints
• Rail splices not supported by attachments

Labeling Requirements: The Fastest Way to Fail

Missing or wrong labels are one of the cheapest items to prevent and one of the easiest for an inspector to see. Labels and placards cost little compared with a return trip.

NEC Labeling Requirements

NEC Article 690 specifies labeling for solar installations, and requirements have changed across code cycles. Check the adopted edition for wording, size, color and placement.

Labels and markings commonly required include:

• Maximum voltage and current information at disconnects and junction boxes where the code calls for it
• Markings on overcurrent protection devices as the code requires for PV circuits
• Rapid shutdown placards at the locations the adopted edition specifies
• Arc-fault protection information where applicable
• Grounding electrode conductor labels

Edition-Specific Labeling Changes

Labeling rules do not stay still across editions. The 2026 edition of the NEC is published by NFPA, which offers free online read access. Before you design to a new edition, read these areas in the edition text rather than in a summary:

• Arc flash and equipment marking requirements in Article 110
• Voltage marking in Article 690
• Energy storage placards and the articles that now cover them (Articles 702, 705 and 706)
• Listing and identification requirements for cable management products

Label Placement Rules

Labels must be placed where the inspector can see them without disassembling equipment:

• Conduit and raceway labels at the intervals the adopted edition requires
• Labels at roof, wall, or barrier penetrations where required
• AC disconnects in locations the fire department can reach
• Inverter labels visible from a standing position

Labels must be weather-resistant. Paper labels in plastic sleeves tend to fail. Use engraved plates or UV-rated vinyl rated for the environment.

Cable Management

Cable ties and clips used outdoors should be rated for sunlight and temperature exposure and be of a type the code and the manufacturer’s instructions accept. Off-the-shelf zip ties from the hardware store are a common failure point on rooftop wiring. An inspector who spots unsuitable ties may require rework, which on a large array takes hours.

The Five Fail Points That Cost Installers the Most Money

These five areas show up again and again in plan reviews and inspection notes: conductor sizing, grounding, rapid shutdown, conduit installation and documentation. Address them and you remove most of the avoidable reasons for a return trip.

Fail Point 1: Incorrect Conductor Sizing

Conductor sizing errors are easy to make and expensive to fix. The usual cause is a worksheet that skips a correction factor or applies the wrong one.

To prevent them:

• Use the factors from the adopted NEC edition, not a rule of thumb
• Show each step on the worksheet so a reviewer can follow it
• Re-run the worksheet if the conduit type, conductor count or conductor size changes in the field
• Match module datasheet values, not nameplate marketing figures

When the worksheet and the install disagree, the inspector will believe the install and the plan reviewer the worksheet. One of them has to change before the visit.

Fail Point 2: Missing or Inadequate Grounding

Grounding failures often require removing modules to reach bonding points, which is why they are costly.

The inspector may test continuity between metal components and the grounding electrode, so test first and keep the results.

Common grounding failures:

• Painted module frames without bonding hardware
• Rail splices without bonding jumpers
• Corroded grounding electrode connections
• Missing equipment grounding conductors in conduit
• Improper grounding electrode conductor sizing

Follow the racking manufacturer’s bonding instructions, and add a bonding jumper at rail splices where the instructions or the AHJ call for one.

Fail Point 3: Rapid Shutdown Non-Compliance

Rapid shutdown failures are serious because they involve life safety.

Common rapid shutdown failures:

• Missing placards at array boundaries
• Inverter and shutdown device incompatibility
• Controlled conductors outside the shutdown boundary
• Labels that do not match the adopted edition’s requirements
• Systems that do not reduce voltage as the code requires when the shutdown device is activated

The functional test is the gate. The inspector activates the rapid shutdown device and checks that the system behaves as the installation instructions and the code describe. Run the same test yourself before the visit and record the result.

Fail Point 4: Conduit Fill and Support Violations

Conduit fill and support spacing are easy to check and easy to fail.

NEC Chapter 9, Table 1 sets maximum fill as a percentage of conduit cross-section, and the percentage depends on the number of conductors. Conduit type matters too, because internal dimensions differ between PVC, EMT and rigid metal conduit. Use the dimension tables in the code for the conduit you installed.

Support spacing is set by the article for each wiring method (for EMT, Article 358). Check supports at terminations, at bends and along straight runs against the article, and measure them. The inspector may do the same with a tape measure.

Fail Point 5: Missing or Incomplete Documentation

Documentation failures are frustrating because they have nothing to do with installation quality. The system is fine. The paperwork is not.

Required documentation at inspection:

• Approved plans with AHJ stamp
• Inspection record card
• Manufacturer installation instructions
• As-built single-line diagram
• Equipment spec sheets
• Torque verification log
• Grounding continuity test results

The inspector will ask for these documents. If the installer cannot produce them, the inspection may stop.

NEC 2026: What Is Changing and When It Matters

The NEC is revised on a three-year cycle, and each state or city adopts a new edition on its own schedule, often with amendments. Most AHJs are on an earlier edition than the newest one, so the question is which edition governs your permit. Ask the AHJ, and check the adoption date against your permit application date.

Projects designed today may be inspected under a newer edition if the AHJ adopts one before completion, so it is worth knowing which articles to read when the AHJ announces an adoption.

Where to Look in the 2026 Edition

The table lists topics worth reading in the edition text. It does not state what changed, because summaries from vendors and training providers differ and the code text governs.

Connector Compatibility

Connectors from different manufacturers can look interchangeable and still mate poorly. Use matched connectors from one manufacturer, or follow written compatibility documentation from the manufacturers involved. Keep that documentation in the project file, because an inspector may ask for it.

Pre-Inspection Checklist: A Printable Framework

Use this checklist before every inspection. Print it. Laminate it. Check every box.

Pre-Inspection Walkthrough

Electrical Verification

Labeling Verification

Documentation Check

What the Data Says: Inspection Failure Patterns

NREL’s SolarAPP+ performance review is the most detailed public inspection-outcome data for U.S. residential solar that this guide draws on. SolarAPP+ is an online platform that checks residential PV applications for code compliance and generates inspection checklists; see the SolarAPP+ site for where it is available. The report covers 2022 data and was published in May 2023. NREL defines the failure rate as the share of projects that failed at least one inspection, measured across 12 AHJs with available data.

Failure Rates by Project Type

Source: NREL SolarAPP+ Performance Review (2022 Data), via OSTI.

NREL says the results suggest SolarAPP+ permitting does not create downstream inspection problems, and may reduce failures. It also says the second point is a working hypothesis, because installers who use the platform may differ from those who do not.

Reasons for Failure (2022 NREL Data)

NREL also tracked why SolarAPP+ projects failed. Of the identified failures:

Work quality issues dominate. These are installation errors, not design errors. The system was designed correctly but installed incorrectly. The 11% tied to SolarAPP+ itself, such as the checklist not being on site, is the kind of failure that preparation removes.

The Cost of Failure

NREL’s report does not price a failed inspection, and cost varies by crew, region and AHJ. Count these line items on your own jobs:

Multiply your own first-time fail rate by the average cost of one failure to see what preparation is worth. For example, a crew that does 100 jobs a year and fails 20 of them has 20 failures to price. Use your fee schedule and labor rates, not a national average.

Regional Differences: How AHJs Vary

Not all AHJs inspect the same way. Understanding your local inspector’s priorities prevents surprises, and the adopted code edition and local amendments are the first thing to check in any new jurisdiction.

California: State Codes and Local Amendments

California combines the California Electrical Code with Title 24 energy requirements and local fire codes. Check with the AHJ for:

• Solar-ready requirements in new construction
• Fire setbacks and pathway requirements
• California Electrical Code amendments
• Interconnection documentation the utility requires

Texas: Local Adoption Matters

Code adoption in Texas varies by city and county, so the edition and amendments can differ between neighboring jurisdictions. Installers working across Texas should verify the code version for every jurisdiction. The same design may pass in one city and fail in another.

Northeast: Older Housing Stock

Northeastern AHJs often deal with older homes. Inspectors may pay extra attention to:

• Service panel capacity and condition
• Existing wiring that may interact with the new circuit
• Structural condition of aging roofs
• Historic district restrictions

An installer who treats a 1920s home like a new build will meet problems at inspection.

Florida: Hurricane and Wind Load Focus

Florida AHJs prioritize wind load and hurricane resistance. Inspectors may check:

• Rail attachment spacing against wind zone requirements
• Module clamp torque values
• Roof penetration waterproofing
• Flood zone requirements where they apply

Wind design values come from the building code and the engineering for the site, not from the electrical code.

Practical Guidance: Building an Inspection-Ready Culture

Passing inspections is not about last-minute fixes. It is about building systems and habits that produce compliant work every time.

Standardize Your Design Process

Every project should use the same design checklist. The checklist should include:

• NEC article references for every design decision
• Conductor sizing with all correction factors shown
• Rapid shutdown boundary verification
• Grounding continuity test points
• Label placement map

Solar design software that supports electrical workflow and array layout in one project reduces re-keying between the plan set and the field. Results still depend on the data and assumptions entered, and the responsible engineer or AHJ approves the final design.

Train for Inspection, Not Just Installation

Most crew training focuses on installation speed and quality. Add inspection preparation to the curriculum:

• What the inspector checks and why
• How to read single-line diagrams
• Grounding continuity testing with a multimeter
• Label placement requirements
• Common failure patterns and how to avoid them

A crew that understands the inspection process installs with compliance in mind. They do not just mount panels. They build systems that pass.

Document Everything

Documentation is not paperwork. It is proof. Every project file should include:

• Pre-installation photos of the roof and electrical panel
• Rough-in photos before walls close
• Torque verification logs for every critical connection
• Grounding continuity test results
• Rapid shutdown functional test results
• Final as-built photos

These documents protect the installer if questions arise later. They also speed up inspections when the inspector asks for verification.

Use a Pre-Inspection Checklist

The checklist in this guide is a starting point. Customize it for your AHJ, your equipment, and your typical projects. Laminate it. Put it on a clipboard. Make it part of every project closeout.

The time spent running through a checklist before calling for inspection saves rework and protects customer relationships.

Frequently Asked Questions

What are the most common reasons solar inspections fail?

In NREL’s 2022 SolarAPP+ review, 58% of identified inspection failures were work quality issues, meaning the system was not installed per code. Rescheduled inspections made up 12% and SolarAPP+ checklist or plan mismatches 11%. Grounding, labeling, rapid shutdown, conduit and missing documents are the usual field causes.

How much does a failed solar inspection cost in rework?

The cost depends on your AHJ fee schedule, crew rates and the fix needed, and NREL’s report does not put a price on it. Count the re-inspection fee, the crew return trip, rework materials and the days PTO is delayed. Multiply by your own failure count.

What NEC version applies to my solar inspection in 2026?

The edition your AHJ has adopted applies, and adoption dates and local amendments differ by state and city. Ask the AHJ which edition governs your permit before you design. Read the adopted edition’s text rather than a summary, because vendor summaries of new editions differ.

What does an AHJ inspector check during a final solar inspection?

The inspector checks the installed system against the approved plans and the adopted code. That covers module placement, labels and placards, grounding and bonding, rapid shutdown, disconnect access and fire pathways. Have the plans, manufacturer instructions, as-built single-line diagram and test records on site.

Do I need an electrical permit and a building permit for solar?

Most jurisdictions require an electrical permit for the wiring and a building or structural permit for roof-mounted arrays, but the exact set depends on the AHJ. Some run a combined solar PV permit, and some also involve the fire department. Check the AHJ’s permit page before you apply.

What is rapid shutdown and why do inspectors care so much?

Rapid shutdown is a safety function, addressed in NEC 690.12, that reduces voltage in certain PV circuits when the system is shut down. It protects firefighters. The limits and boundaries depend on the adopted NEC edition, so inspectors check device placement, labels and the functional test.

What is the difference between a rough-in and final inspection?

A rough-in inspection happens after conduit and wiring are installed but before they are covered, and it checks routing, sizing and grounding. A final inspection happens after all work is complete and checks the whole system, including labels, function and code compliance.

Conclusion: Three Actions for Your Next Inspection

• Print the checklist from this guide and use it before every inspection. Verifying labels, grounding, conduit, and documentation before the call is cheaper than a return trip.

• Test grounding continuity before the inspector arrives. Do not assume mechanical connections are sufficient. Measure every bonding point against the manufacturer’s criteria and record the result.

• Check your AHJ’s adopted NEC edition before starting design. A system designed for one edition may fail under another edition’s requirements. Know the code your inspector enforces.

Inspections are quality gates, not obstacles. Installers who use them to verify their own work build better systems and spend less time on callbacks. To model the layout and electrical design before the crew arrives, book a SurgePV demo.

Related SurgePV Resources

Continue learning with these related guides for solar installers and EPCs:

• OSHA Compliance Checklist for Solar Installers
• How to Expedite Solar Permits
• Change Order Management for Commercial Solar
• Handling Customer Complaints After Solar Installation
• Solar Installer Insurance Requirements

For more solar business and marketing content, explore the full SurgePV blog or browse the SurgePV glossary for definitions of solar industry terms.

Solar Software Tools to Support This Work

SurgePV’s cloud solar design software supports the upstream work that feeds every decision in this guide:

• Solar design software for system layouts, panel placement, and BOM generation
• Shadow analysis for site-specific irradiance and obstruction modeling
• Solar financial modeling for production forecasts and project ROI
• Solar proposal generation for branded, customer-facing proposals
• Clara AI for automated design assistance

Browse the full SurgePV platform to see the full toolset.