Solar Panel Inspection: What Every Inspector Should Check & Document

Solar panel inspections are no longer a niche specialty — they're becoming a standard part of residential inspections across the country. With over 5 million residential solar installations in the U.S. and the number climbing fast, every working home inspector needs a solid solar panel inspection checklist and the confidence to evaluate these systems in the field.

Here's the reality: most home inspection training programs still treat solar as an afterthought. A paragraph in the electrical chapter, maybe a slide or two. But when you're standing on a roof looking at 30 panels, a string inverter on the side of the house, conduit runs through the attic, and a rapid shutdown system you've never seen before — that paragraph isn't going to cut it.

This guide covers everything you need to inspect and document on a residential solar installation, from the roof penetrations to the electrical disconnect. We'll cover what's in your scope, what requires an electrician referral, and how to document it all without spending an extra hour on site.

Why Solar Inspections Matter Now

The numbers tell the story. Residential solar installations have grown roughly 20–25% year-over-year since 2020. In states like California, Arizona, Texas, Florida, and the entire Northeast corridor, you'll encounter solar on a significant percentage of homes.

For inspectors, this means:

• Buyers expect you to evaluate the solar system — even if your state standards of practice don't explicitly require it
• Agents are asking about solar condition during the inspection process
• Improperly installed solar creates real risks — roof leaks, electrical fires, code violations, and voided roof warranties
• Solar adds complexity to your electrical inspection and roofing inspection

Ignoring solar or writing "solar panels present — recommend evaluation by qualified solar contractor" for every system is leaving money and credibility on the table. You don't need to be an electrician, but you do need to know what to look at.

What's In Your Scope vs. What Requires Referral

Let's set boundaries first. As a home inspector, you can — and should — evaluate:

In Your Scope:

• Roof mounting and penetration condition
• Racking system condition (visible)
• Panel physical condition (from roof or with binoculars/drone)
• Conduit and wiring runs (visible portions)
• Inverter location, condition, and type identification
• Electrical disconnect presence and labeling
• Rapid shutdown signage and compliance indicators
• Visible safety concerns
• General system documentation

Refer to Licensed Electrician or Solar Contractor:

• Performance testing or production verification requiring system access
• Electrical connections inside combiner boxes, junction boxes, or inverters
• Microinverter diagnostics
• String voltage or current measurements
• Any work requiring interaction with energized DC components
• Warranty or production guarantee evaluation

The Solar Panel Inspection Checklist

1. Roof Mounting and Penetrations

This is where solar installations most commonly create problems, and it's squarely in your wheelhouse as an inspector. Every roof-mounted solar array requires penetrations through the roofing material, and every penetration is a potential leak point.

What to check:

• Flashing condition — Each mounting point (lag bolt into rafter) should have proper flashing. Look for:
  • Flashed standoffs/mounts with intact sealant
  • No lifted or cracked flashing
  • Proper integration with surrounding roofing material (shingles should overlap flashing on the upslope side)
• Lag bolt locations — Mounts should be fastened into rafters, not just roof sheathing. You can sometimes verify this by checking bolt spacing against typical rafter layouts (16" or 24" on center).
• Standoff condition — Check for corrosion, loose hardware, or standoffs that appear to have shifted
• Sealant/caulking — Note any sealant that's cracked, dried out, or deteriorating around penetrations
• Water staining below — If accessible, check the attic space below the array for any signs of water intrusion at penetration points. Reference our attic inspection guide for thorough attic evaluation.
• Roof condition around the array — Is there debris accumulation at the bottom edge of the panels? Are shingles damaged from installation?

2. Racking System Condition

The racking system is the aluminum (or sometimes steel) framework that holds panels to the standoffs. It's the skeleton of the installation.

What to check:

• Rail condition — Look for corrosion, bending, or physical damage to rails
• Mid-clamps and end-clamps — These hold panels to the rails. Check for missing, loose, or damaged clamps
• Rail splices — Where two rail sections join, check for proper connection and hardware
• Ground lugs — Racking should be grounded. Look for green grounding lugs and ground wire connections on rails
• Spacing — Panels should have consistent spacing from the roof surface (typically 3–6 inches for airflow) and between panels
• Fire setbacks — Many jurisdictions require setbacks from roof edges and ridgelines for firefighter access. While code enforcement isn't your job, noting obvious violations is helpful to buyers.

3. Panel Condition

You're evaluating the physical condition of the panels themselves. You don't need to test electrical output — that's a performance evaluation outside your scope.

What to check:

• Cracking — Inspect glass surfaces for cracks or chips. Even small cracks can allow moisture intrusion that degrades cells over time.
• Discoloration — Browning or yellowing of the encapsulant (the layer between glass and cells) indicates UV degradation. Some discoloration on 10+ year old panels is normal. Significant browning on newer panels is not.
• Hot spots — You won't see these visually, but if you have a thermal imaging camera, solar panels are a perfect application. Hot spots indicate failing cells or connection issues.
• Delamination — Separation of the layers within the panel. Look for bubbling, peeling, or moisture between layers.
• Physical damage — Hail damage, fallen branch impacts, animal damage (squirrels love to nest under panels and chew wiring)
• Soiling — Heavy dirt, bird droppings, or leaf accumulation reduces output significantly. Note excessive soiling as a maintenance item.
• Panel count and layout — Document the number of panels and the general layout (orientation, tilt, which roof faces). This helps buyers understand the system they're acquiring.

4. Wiring and Conduit Runs

Trace the visible wiring path from the array to the inverter and from the inverter to the electrical panel.

What to check:

• Conduit type and condition — Exterior conduit should be appropriate for outdoor use (typically EMT or rigid PVC/schedule 40 depending on location). Check for:
  • UV degradation on PVC conduit
  • Loose or missing conduit clamps
  • Unsupported runs
  • Damaged or crushed sections
• Conduit routing — Runs should be neat, properly supported, and protected from physical damage
• Exposed wiring — Any wiring outside of conduit that should be in conduit is a deficiency. The exception is USE-2/PV wire rated for exposed outdoor use in certain applications.
• Penetrations into the building — Where conduit enters the attic or building interior, check for proper sealing and fire-stopping
• Wire management under the array — Wiring under panels should be secured to racking with clips, not hanging loose where it can chafe against the roof or racking
• Animal damage — Squirrels and rodents chew through PV wire insulation. Look for chew marks, especially at roof level.

5. Inverter Inspection

The inverter converts DC power from the panels to AC power for the home. There are two main types, and knowing which you're looking at changes what you check.

String Inverters:

• Typically a large box mounted on the exterior wall near the main panel
• Check for proper mounting height (not too close to ground), ventilation clearance, and weather protection
• Look for error codes or warning lights on the display
• Note the manufacturer, model, and any visible production data
• Check for signs of overheating — discoloration, melted components, burn marks

Microinverters:

• Small inverters mounted under each panel on the racking
• You won't typically access these directly
• Check for visible wiring connections at accessible microinverters
• The monitoring system (if present) is the primary way to evaluate microinverter health — note whether monitoring is active

What to check on any inverter:

• Mounting and weatherproofing — Secure mounting, appropriate location (shaded is better for longevity)
• Ventilation — Adequate clearance for airflow. No debris blocking vents.
• Wiring connections — Visible connections should be in appropriate enclosures with proper strain relief
• Labeling — Inverter should have clear labeling with manufacturer, ratings, and installation date
• Error indicators — Red lights, error codes, or blank displays suggest system issues

6. Rapid Shutdown Compliance (NEC 690.12)

This is important enough to get its own section. NEC 690.12 requires rapid shutdown capability for solar systems to protect firefighters and first responders.

What to check:

• Rapid shutdown signage — A placard should be posted at the main service panel indicating the presence of a PV system and rapid shutdown equipment. Look for the standard fire safety placard.
• Rapid shutdown initiation device — Typically integrated into the inverter, a dedicated device near the main panel, or accomplished through microinverter communication
• Additional signage — Placards on the meter, at the point of interconnection, and potentially on the roof near the array
• System type — Module-level shutdown (microinverters or DC optimizers) inherently meets 690.12. String inverter systems may need additional rapid shutdown equipment.

You're not testing the rapid shutdown system — that requires specialized equipment and is outside your scope. But noting the presence or absence of required signage and visible shutdown equipment is within scope and valuable to buyers.

7. Electrical Connections and Disconnect

What to check:

• AC disconnect — There should be a visible, accessible AC disconnect between the inverter and the main panel. Note its location and condition.
• Backfeed breaker — In the main electrical panel, the solar connection typically comes in through a dedicated breaker. Note its location, amperage rating, and labeling. Per NEC, it should be at the opposite end of the bus from the main breaker. Reference our electrical inspection checklist for panel evaluation.
• Production meter — Some systems have a separate production meter. Note its presence if applicable.
• Grounding — The system should have a properly sized equipment grounding conductor. Look for ground rods or connections to the building's grounding electrode system.
• Labeling — All disconnects, breakers, and junction boxes associated with the solar system should be clearly labeled per NEC requirements.

8. Roof Condition Under and Around Panels

This is often overlooked but critically important.

• Shingle condition — If you can see under the array edges, note the condition of roofing material beneath the panels
• Roof age vs. panel age — If the roof is nearing end of life but the panels are relatively new, note that removing panels for a roof replacement adds $2,000–$5,000+ to the re-roofing cost
• Debris accumulation — Leaves and debris collect at the lower edge of panel arrays. This traps moisture and accelerates shingle degradation.
• Ventilation — Panel arrays can affect roof ventilation patterns. Check that ridge vents and soffit vents aren't blocked or compromised by the installation.

Check our roofing inspection checklist for full roof evaluation guidance.

9. Production Monitoring

Many solar systems include monitoring that tracks daily, monthly, and annual production. While testing the system is outside your scope, documenting what's available is helpful:

• Note whether a monitoring system is present (app-based, web portal, inverter display)
• If the homeowner can show production data, document whether the system appears to be producing. A system producing zero or significantly below expected output is worth noting.
• Note the system's nameplate capacity (total kW) if visible on inverter labeling or monitoring

Documentation Tips for Solar Inspections

Solar documentation doesn't need to be complicated, but it needs to be thorough enough to protect you and inform the buyer.

Always document:

1. System overview — panel count, estimated array size (kW if visible), inverter type and manufacturer
2. Roof mounting condition — overall assessment of penetration integrity
3. Any visible deficiencies — cracking, wiring issues, missing hardware, improper conduit
4. Presence/absence of required signage and disconnects
5. Roof condition relative to panel age — flag the re-roofing cost issue if applicable
6. Referral recommendations — when to recommend a licensed electrician or solar contractor for further evaluation

Photo documentation essentials:

• Overall array layout (ideally from ground with a wide-angle shot)
• Inverter with labeling visible
• Electrical disconnect and panel connections
• Any deficiencies found
• Conduit routing
• Rapid shutdown signage

When to Refer to an Electrician

Always recommend further evaluation by a licensed electrician or qualified solar contractor when you observe:

• Any signs of arcing, burning, or melting at electrical connections
• Missing or non-functional rapid shutdown equipment
• Open or damaged junction boxes or combiner boxes
• Improperly rated or missing AC disconnect
• The buyer wants a performance verification or production guarantee evaluation
• The system appears to be non-functional (blank inverter display, no production)
• Any DC wiring concerns — never interact with DC solar wiring yourself
• The system was installed without permits (check with the local building department if uncertain)

Common Solar Installation Issues to Watch For

After inspecting hundreds of solar installations, here are the most common issues inspectors find:

1. Inadequate flashing — Especially on DIY installations or older systems installed before current best practices
2. Missing conduit clamps — Conduit runs that are unsupported or loosely attached
3. Squirrel damage — Chewed wire insulation under the array is extremely common
4. Missing signage — Rapid shutdown and electrical warning placards absent or illegible
5. Backfeed breaker at wrong location — Should be at the opposite end of the bus from the main breaker
6. Debris accumulation — Leaf and dirt buildup at panel edges causing moisture issues
7. Sealant degradation — Original sealant at penetrations drying out and cracking after 5+ years

Solar inspections are a growing part of every home inspector's workload. For more specialty inspection guides, check out our thermal imaging guide, electrical inspection checklist, and drone roof inspection guide.