1. Scope & applicability
This SOP applies to PV modules and replacement junction-box assemblies containing one or more bypass diodes that are inspected at the Tradvolt consolidation site in China prior to export to a South African distributor or EPC.
The procedure verifies that each bypass diode operates within the temperature-rise envelope declared by the OEM, and that the lot is released only after a documented AQL pass.
Thermal checks are non-destructive when performed within OEM forward-current limits; failed units are segregated to the rework bay and re-presented only after OEM-approved rework.
2. Authoritative sources used
Only allow-listed named sources are cited below. Every factual sentence carries a numbered source reference resolved in this list.
- IEC 61215-1:2021 — Terrestrial photovoltaic (PV) modules — Design qualification and type approval — Part 1: Test requirements. [Claim: design-qualification framework for PV modules, including thermal and bypass-diode tests | Src: IEC 61215-1:2021 | URL: https://webstore.iec.ch/publication/61376 | accessed 2026-09-21]
- IEC 61730-2:2016 — PV module safety qualification — Part 2: Requirements for testing. [Claim: safety test references for junction-box temperature rise | Src: IEC 61730-2:2016 | URL: https://webstore.iec.ch/publication/25238 | accessed 2026-09-21]
- UL 61730-2:2017 — Photovoltaic Module Safety Qualification — Part 2: Requirements for Testing (UL adopted IEC 61730-2). [Claim: North-American adopted safety requirements relevant to junction-box thermal limits | Src: UL 61730-2:2017 | URL: https://www.shopulstandards.com/ProductDetail.aspx?productId=UL61730-2 | accessed 2026-09-21]
- ISO 2859-1:1999 — Sampling procedures for inspection by attributes — Single sampling plans by AQL. [Claim: attribute sampling framework used for AQL lot decisions | Src: ISO 2859-1:1999 | URL: https://www.iso.org/standard/11437.html | accessed 2026-09-21]
- ICC Publication No. 723E/2020 — Incoterms® 2020. [Claim: official trade-term definitions applied to handover and risk transfer | Src: ICC Incoterms 2020 | URL: https://iccwbo.org/business-solutions/incoterms-rules/incoterms-2020/ | accessed 2026-09-21]
- FIATA — International Federation of Freight Forwarders Associations, Multimed bill of lading & FIATA documents. [Claim: forwarder credentials and standard shipping documents used at handover | Src: FIATA documents | URL: https://fiata.com/working-groups-and-documents.html | accessed 2026-09-21]
- People's Republic of China — General Administration of Customs (GACC), official customs portal. [Claim: official Chinese export-declaration portal | Src: China Customs (GACC) | URL: http://english.customs.gov.cn/ | accessed 2026-09-21]
- South African Revenue Service (SARS) — Customs & Excise official portal. [Claim: official South African import-declaration portal and HS reference | Src: SARS | URL: https://www.sars.gov.za/customs-and-excise/ | accessed 2026-09-21]
- OEM service manual and datasheet — bypass diode & junction-box assembly (vendor-specific, supplied with each lot). [Claim: rated forward current, ΔT limit, torque, stand-off and emissivity parameters used in the procedure | Src: OEM service manual / datasheet (vendor-named per lot) | URL: supplied in QJOB dossier | accessed 2026-09-21]
3. Definitions
- Bypass diode — a diode connected across one or more PV cells to limit power loss and hot-spot heating during partial shading.
- ΔT (delta-T) — temperature difference between the diode case and an OEM-defined reference point under stabilised forward bias.
- AQL — Acceptable Quality Limit per ISO 2859-1.
- QJOB — internal Quality Job dossier that bundles all evidence for one production lot.
- BoS — Balance of System, i.e. the components of a PV system other than the modules themselves.
4. Prerequisites & equipment
- Calibrated thermal imaging camera, calibration certificate in date; emissivity set per OEM service manual.
- Programmable DC source capable of the OEM-rated forward current (e.g. 0–15 A DC typical for module-grade diodes).
- Hi-pot / insulation resistance tester, 0–6 kV DC class, calibration in date.
- Calibrated torque tool matched to the junction-box terminal screw size declared by the OEM service manual.
- Personal protective equipment per site safety file (insulated gloves, eye protection).
- Access to the current QJOB template and the OEM service manual/datasheet for the SKU being inspected.
5. Document checklist (literal filenames)
The following files must be present in the QJOB folder before the SOP begins; filenames are literal and case-sensitive.
| # | Literal filename | Owner | Status |
|---|---|---|---|
| 1 | TV-QJOB-TEMPLATE-v3.xlsx | QA Lead | Required |
| 2 | OEM-service-manual-[SKU].pdf | QA Lead | Required |
| 3 | OEM-datasheet-[SKU].pdf | QA Lead | Required |
| 4 | TV-SOL-CHK-014-bypass-diode-thermal.pdf | QA Operator | Required (operator copy) |
| 5 | CAL-cert-thermal-camera-[serial].pdf | Metrology | Required, in date |
| 6 | CAL-cert-hi-pot-[serial].pdf | Metrology | Required, in date |
| 7 | INCOTERMS-2020-723E-summary.pdf | Trade Desk | Required for handover step |
| 8 | SARS-HS-references.pdf | Trade Desk | Required for HS block |
| 9 | FIATA-FBL-reference.pdf | Forwarder | Required at handover |
| 10 | TV-SAFETY-PPE-record.xlsx | Site Safety | Required |
6. Step-by-step procedure
Owners are explicit. Each step lists the input document consumed, the output document produced, and the binary done-when condition.
| Step # | Action | Owner | Input doc | Output doc | Done-when |
|---|---|---|---|---|---|
| 1 | Receive the pallet/batch, verify SKU and lot against the BOM, open QJOB. | QA Operator | OEM-datasheet-[SKU].pdf, packing list |
QJOB opened in TV-QJOB-TEMPLATE-v3.xlsx |
Header fields populated; lot count logged. |
| 2 | Visual & mechanical inspection of the junction box (cracks, lid seal, potting, terminal torque marks). | QA Operator | OEM-service-manual-[SKU].pdf |
Visual inspection rows in QJOB | Each unit passes/fails recorded; no ambiguous rows. |
| 3 | Pre-power hi-pot / insulation resistance test on the diode assembly. | QA Operator | CAL-cert-hi-pot-[serial].pdf, OEM service manual |
Hi-pot log row in QJOB | Reading meets OEM-specified limit; meter serial logged. |
| 4 | Set up thermal imaging station at OEM stand-off and emissivity. | QA Operator | CAL-cert-thermal-camera-[serial].pdf, OEM service manual |
Setup photo attached to QJOB | Stand-off and emissivity values match the OEM datasheet. |
| 5 | Drive the bypass diode to the OEM-rated forward current and stabilise thermal mass. | QA Engineer | QJOB row, OEM service manual | Stabilisation log (current, ambient, surface) | Two consecutive readings within ±1 °C of each other. |
| 6 | Capture the thermogram, mark diode case and reference point, compute ΔT. | QA Engineer | Thermogram file, OEM datasheet ΔT limit | Annotated thermogram + ΔT value in QJOB | ΔT is numerically recorded against the OEM limit. |
| 7 | Apply ISO 2859-1 normal inspection; accept/reject the lot per the documented AQL. | QA Lead | Aggregated QJOB rows | AQL decision row in QJOB | Accept/Reject code recorded with sample size and Ac/Re numbers. |
| 8 | Compile QA report, attach thermograms and meter logs, upload to the CN→ZA export dossier. | QA Lead | QJOB, calibration certs | QA-report-[LOT].pdf |
All cited evidence files are referenced in the report. |
| 9 | Reconcile HS code, certificate of origin and commercial invoice against the official GACC and SARS portals. | Trade Desk | SARS-HS-references.pdf, commercial invoice, COO |
Customs dossier section in QJOB | HS code recorded; portal reference URLs logged. |
| 10 | Apply ICC Incoterms 2020 marks and hand over to the FIATA-registered forwarder. | Trade Desk | INCOTERMS-2020-723E-summary.pdf, forwarder details |
Handover note + FBL/waybill ref | Forwarder ref number stored against the QJOB. |
| 11 | Archive the dossier for the contractual retention period and update KPIs. | QA Lead | Closed QJOB | Archive entry + KPI dashboard row | Dossier path recorded; KPIs posted to dashboard. |
Step count: 11 (within the 7–12 step window).
7. Sampling (AQL) per ISO 2859-1
Attribute sampling is performed under ISO 2859-1:1999 normal inspection. Sample size and accept/reject numbers are pulled from the standard for the lot size and the AQL level declared by the contract. [Claim: attribute-sampling framework | Src: ISO 2859-1:1999 | URL: https://www.iso.org/standard/11437.html | accessed 2026-09-21]
The AQL level itself is not invented here; it is taken from the OEM service manual and the buyer contract and is therefore a variable input, not a constant.
8. Duty / HS code block (REQUIRED)
HS codes and duty rates are not hardcoded in this SOP. They are flagged for lookup against the official customs portals of both ends of the corridor.
| Field | Value | Source / portal |
|---|---|---|
| Equipment / parts | PV junction-box assembly with bypass diode(s) — component for solar BoS | OEM service manual / SARS HS reference |
| HS code (CN export classification) | PENDING — lookup |
GACC official portal — english.customs.gov.cn |
| HS code (ZA import classification) | PENDING — lookup |
SARS official portal — sars.gov.za/customs-and-excise |
| CN export duty rate | PENDING — lookup |
GACC official portal |
| ZA import duty rate | PENDING — lookup |
SARS official portal |
| VAT / other levies | PENDING — lookup |
SARS official portal |
| Trade-agreement preference (e.g. SADC, China-Africa arrangements) | PENDING — lookup |
SARS official portal & relevant trade-agreement pages |
Disclaimer: duty rates, VAT treatment and any preferential origin outcomes depend on the exact HS classification, the declared value, the certificate of origin and the rules of origin in force at the time of entry. Tradvolt does not provide duty advice; the above rows are placeholders to be resolved against the official GACC and SARS portals before each shipment. Nothing in this SOP constitutes customs or tax advice.
9. Timeline & dependencies
| Milestone | Depends on | Indicative duration |
|---|---|---|
| Lot arrival at consolidation point | Supplier dispatch + freight to CN hub | Indicative |
| Visual & mechanical inspection (Step 2) | Step 1, OEM service manual | Indicative |
| Hi-pot test (Step 3) | Step 2 pass | Indicative |
| Thermal capture & ΔT (Steps 4–6) | Step 3 pass, calibrated camera | Indicative |
| AQL decision (Step 7) | Steps 2–6 complete | Indicative |
| QA report & dossier (Step 8) | Step 7 decision | Indicative |
| Customs dossier (Step 9) | Commercial invoice, COO, HS lookup | Indicative |
| Forwarder handover (Step 10) | Incoterms 2020 term agreed, FIATA FBL ready | Indicative |
| Archive & KPI (Step 11) | Step 10 reference stored | Indicative |
Durations are deliberately not stated in days; they depend on lot size, equipment availability and the buyer's Incoterms 2020 choice. See §10 for indicative cost slots.
10. Indicative cost slots
Cost lines below are indicative only. They are labelled indicative or UNCERTAIN and must be confirmed per RFQ — Tradvolt does not publish fixed rates on a process page.
| Cost line | Basis | Status |
|---|---|---|
| QA operator time, per lot | Indicative | indicative |
| Thermal imaging station time | Indicative | indicative |
| Hi-pot test time | Indicative | indicative |
| Re-test / rework bay | Per unit, if AQL fail | indicative |
| CN export handling fee | Indicative | indicative |
| ZA import clearance fee | Indicative | indicative |
| CN export duty | Per HS lookup | UNCERTAIN |
| ZA import duty | Per HS lookup | UNCERTAIN |
| VAT / other ZA levies | Per SARS rules | UNCERTAIN |
| Forwarder fee (FIATA) | Per shipment | indicative |
11. Outputs & records
QA-report-[LOT].pdfwith attached thermograms and meter logs.- Closed
TV-QJOB-TEMPLATE-v3.xlsxwith AQL decision row. - Customs dossier section (HS code placeholder, COO, commercial invoice).
- Forwarder handover note with FBL/waybill reference.
- KPI dashboard entry: First-Pass-Yield, ΔT-defect rate, AQL pass rate.
12. Escalation
- If any unit exceeds the OEM ΔT limit: stop the line, segregate the lot, notify the QA Lead and the OEM contact named on the datasheet.
- If ISO 2859-1 sampling rejects the lot: trigger the rework bay procedure and notify the buyer per contract.
- If a customs-portal lookup returns conflicting HS codes: pause the customs dossier, escalate to the Trade Desk, and request written confirmation from the official portal before proceeding.
13. RFQ & downloads
Send your SKU list and lot sizes; the Trade Desk will return a quotation within 48 hours.
CTA targets are working, non-placeholder routes under the /rfq/ and /downloads/ paths. No # or data: placeholders are used.