Price is the last thing that decides a solar equipment order. Before that, someone on the buyer’s side has to answer a harder question: will this supplier still be accountable in year ten, and can the paperwork survive a review? Qualification is where that gets settled, and it is the step most projects skip because it looks like overhead.
This page is for EPCs, developers and procurement teams assessing a supplier for the first time, and for anyone who has been asked to sign off on a purchase they have not seen produced. It covers what a factory audit actually looks at, what to request before anyone travels, the three kinds of third-party inspection and what each one catches, how to check that a certificate is real, and what to do when an audit finds something wrong.
Why qualification comes before price
Two quotes can be close in dollars and very far apart in risk. The difference is usually not the equipment — it is whether the documentation will pass review, whether a defect found after energisation gets resolved or argued about, and whether the same specification is available again when the project is extended.
Qualification is cheap relative to any of those. A site visit and a pre-shipment inspection cost a fraction of a single container, and they are the only way to find out whether the process behind the quote exists or was assembled to win the order.
What a factory audit actually looks at
An audit is not a tour. It is three separate questions, and a supplier can pass one and fail another.
Reference table
Swipe horizontally to view all columns →
| Dimension | What is being checked | What a weak answer looks like |
|---|---|---|
| Capability | Does the line that makes this product exist, and is it running | Photos of a line that is not the one making your order |
| Quality system | Are inspection records kept, and can a unit be traced back to a batch | Records created on request rather than as work proceeds |
| Compliance | Do the certifications cover the specific model and capacity being quoted | A certificate for a different model, or one that expired |
The third row is where most disputes start. A certificate held by a company is not the same as a certificate covering the exact model, capacity and configuration being supplied.
What to request before anyone travels
Sending this list first saves a wasted visit, because a supplier who cannot produce it usually cannot produce it on site either.
- Certificates for the exact model — listing reports and test reports, not a marketing summary.
- A recent datasheet and revision history — so you can tell whether the specification you were quoted is the current one.
- An inspection report from a previous shipment — any third-party report from the last few months.
- Traceability example — one serial number traced back through production records to its component batches.
- Capacity and scheduling answer in writing — what can be produced in the window you need, stated as a range rather than a promise.
If the answers arrive quickly and are specific, the audit is usually a formality. If they arrive slowly and generically, that is the finding.
On site: what to actually look at
Three things are worth more than the rest of the visit.
- Inspection records as work proceeds. Ask for the record for a unit currently on the line, not a completed one. Records generated live are difficult to fabricate and easy to recognise.
- The incoming material area. What is being received, and is anything being held as nonconforming. A supplier with no quarantine area is not segregating anything.
- Finished goods storage. How units are stacked, whether anything is stored outdoors that should not be, and how long the oldest unit has been sitting there.
None of this requires specialist knowledge. It requires asking to see the process rather than the showroom.
The three kinds of third-party inspection
Reference table
Swipe horizontally to view all columns →
| Type | When it happens | What it catches |
|---|---|---|
| Pre-production | Before the run starts | Wrong components specified, wrong configuration agreed |
| During production | Mid-run | Process drift, workmanship issues while they can still be corrected |
| Pre-shipment | After packing, before loading | Quantity, packaging, labelling, specification against the order |
Pre-shipment is the most commonly ordered and the least useful on its own, because by then the only remedy is rework or rejection. Where the order is large enough to justify it, a during-production visit is the one that changes outcomes.
Sampling: what is realistic
Inspection is statistical, and buyers are often quoted a sampling level without being told what it means. A standard general inspection level gives a sample size that grows with the order, and the acceptance thresholds differ by defect class — critical, major and minor.
Two practical points. First, agree the defect classification in writing before the inspection, because “major” means different things to different inspectors. Second, for photovoltaic equipment, some checks are not statistical at all — a flash test result or a serial number scan can be run across every unit, and should be.
How to check a certificate is real
This takes minutes and is worth doing before the order, not after delivery.
- Verify the listing in the certifier’s own directory. UL listings can be checked in UL Product iQ by company name or file number; ETL listings are verified through the Intertek directory. A certificate PDF is a document; the directory entry is the record.
- Match the file number to the model. The listing has to cover the model and rating being quoted, not a family name.
- Check the status, not just the existence. Listings can be withdrawn or limited in scope, and the current status is what an authority will see.
- Ask for the test report behind the listing. For storage equipment, reviewers frequently ask for the thermal test report for the specific capacity, and that is a separate document from the listing itself.
When an audit finds something
It usually does. The response is what matters.
A minor nonconformance with a specific correction and a date is a normal outcome. Ask for the corrective action in writing and confirm it at the next inspection.
A finding that affects the product — a component that is not what was specified, a test that was skipped — is a decision point. Either the order is re-specified and re-quoted, or it is stopped. Continuing with a known deviation and hoping it passes review is how equipment gets rejected at the site rather than at the factory.
A refusal to allow inspection is itself the answer, and it is the one finding that should end the conversation.
What qualification costs and how long it takes
Both depend on scope, location and whether travel is involved, so the honest answer is per enquiry rather than a number. What can be said in general: a documentation review is days, a site visit is a trip, and pre-shipment inspection is priced per man-day. Where a stamped structural calculation or a witnessed test is required, that has to be on the original enquiry so it is scheduled rather than added later.
The scheduling point is the one that causes trouble. A requirement discovered after the order is placed is a change; the same requirement on the enquiry is a line item.
How this fits the rest of the purchase
Qualification sits alongside three other things, and it is worth reading them together. The documentation that has to travel with the equipment is set out in the resources page; the sequence of checks from order to delivery is in the importing checklist; and for US projects, sourcing rules that affect where equipment can come from are covered in the FEOC sourcing guide.
What a supplier commits to when something does go wrong is the other half of the question, and it is written down rather than asserted — see service quality and claims. The equipment itself is catalogued by category under products, each with the documentation supplied with it.
If you are qualifying a supplier now and want the documentation set before you commit, send the models and quantities you are pricing and the standards the project has to meet.
BUYER CHECKLIST
Buyer considerations for this scope
Is the audit scope tied to the model being quoted?
A certificate or an audit held by a company does not automatically cover the model, capacity and configuration on your quote. Ask for the listing report and the test report for the exact item, and match the file number before the order rather than after delivery.
Is inspection scheduled on the original enquiry?
A requirement discovered after the order is placed is a change; the same requirement on the enquiry is a line item. If a witnessed test, a stamped calculation or a during-production inspection will be needed, put it on the enquiry so it is priced and scheduled.
What is the corrective-action route before anything goes wrong?
Ask what happens when something is found, before something is found. You want a stated corrective action with a date for minor findings, and a clear position on who pays and who decides when a finding affects the product itself. That answer is worth more than the audit score.
PRACTICAL ANSWERS
Questions buyers ask about this
Do we need a factory audit for every order?
Not usually for every order. Qualification is done once and then maintained: a full audit for a first purchase or a new product category, and inspection on subsequent shipments. What changes the answer is whether the specification, the production line or the volume has changed since the last audit.
What is the difference between a factory audit and a pre-shipment inspection?
An audit looks at the supplier capability, quality system and compliance, which is whether the process exists at all. A pre-shipment inspection looks at this order: quantity, packaging, labelling and specification against what was agreed. They answer different questions and one does not substitute for the other.
How do we verify that a UL or ETL certificate is genuine?
Check the listing in the certifier directory rather than relying on the PDF. UL listings can be looked up in UL Product iQ by company or file number, and ETL listings through the Intertek directory. Match the file number to the exact model and rating, and confirm the current status rather than only that a listing exists.
What should we do if an inspection finds a nonconformance?
Separate it by severity. A minor issue with a stated correction and a date is a normal outcome, so get the corrective action in writing and confirm it next time. A finding that affects the product itself, such as a component that is not what was specified, is a decision point: re-specify and re-quote, or stop. A refusal to allow inspection ends the conversation.
EXPLORE FURTHER