DIY Solar Inspection: What Inspectors Check and Why Installs Fail

Failing a solar inspection is common for first-time DIY installers, and the reasons are almost never the difficult parts of the job. Arrays rarely fail on string design or racking. They fail on labels, bonding and disconnect placement — items that take an afternoon to get right and cost a two-week rescheduling delay to get wrong.

The five most common failures

1. Labelling. Placards at the service equipment, labels on disconnects, conductor identification, and the plaque showing the point of interconnection. This is the most frequently failed item in DIY solar and the easiest to fix — it is stickers and a label maker, and inspectors check every one.
2. Grounding and bonding. Module frames bonded to racking, racking bonded to the equipment grounding conductor, everything back to the grounding electrode system. Where racking bonds through the clamps, inspectors check that the correct clamps were used in the correct places.
3. Disconnect accessibility. Disconnects must be reachable, correctly located and properly marked. A DC disconnect tucked behind the inverter where nobody can reach it in an emergency fails.
4. Rapid shutdown. Recent NEC editions require module-level shutdown on rooftop arrays. A plain string inverter with no optimisers or shutdown devices does not pass under those editions, and this one cannot be fixed on the day.
5. Wire management. Conductors resting on the roof surface, unsupported runs, missing conduit where required, or cable ties that will not survive UV exposure.

Four of those five are correctable in an afternoon. The fifth — rapid shutdown — is a design decision that must be right before you order equipment, which is why confirming your jurisdiction's adopted NEC edition before designing matters so much.

What else the inspector looks at

That final row catches people. If you improved something during installation — moved a disconnect, changed a string configuration, used a different inverter — it no longer matches the approved plan, and inspectors reject deviations even when the change is technically better. If you must deviate, contact the department before the inspection rather than hoping it passes.

How to prepare

• Have the approved plan set on site, printed, along with equipment cut sheets
• Walk your own installation against the plan the day before, line by line
• Check every label against the plan's labelling schedule
• Verify every bonding connection physically, including ones you are sure about
• Make everything accessible — do not close up conduit or panels the inspector needs to see inside
• Be present. Being there to answer questions turns some marginal items into a conversation rather than a rejection

If you fail

It is routine and not a disaster. You will get a correction notice listing the items, you fix them and reschedule. What it costs is time — typically another one to three weeks for a slot, plus a re-inspection fee in some jurisdictions.

The way to avoid a second failure is to ask the inspector directly what they want to see on the items they flagged. Inspectors are generally willing to explain, and a specific answer from the person who will re-inspect beats interpreting the code yourself.

The cheapest insurance available

Have a licensed electrician review the installation before the inspection. At $100-200 for an hour, someone who has been through dozens of these will spot the labelling gap, the missing bond and the inaccessible disconnect in minutes. Against a two-to-three-week rescheduling delay, it is the best-value hour in the whole project — as covered in hiring an electrician for the final hookup.

Requirements vary by adopted code edition and local amendment, so treat this as the common pattern rather than a checklist for your jurisdiction. Your inspector and your adopted code are the authority.