Maintenance Guide: DC-String-Reverse Process for CN→LATAM Photovoltaic Trade Corridors

Verdict in 100 words. Expected duration: 10 working days (Day 0 scope memo → Day 10 LATAM-side receipt) for a typical 20-foot GP / 40-foot GP lot of N-type TOPCon modules (example model: Jinko Tiger Neo JKM-N-54HL4R-V, 54-cell bifacial, Voc 29.42 V at STC, Max series fuse 25 A per OEM datasheet). Equipment/location: CN-origin factory warehouse → LATAM destination port (model assumption: Manzanillo, MX or Buenaventura, CO). Horizon: 7–10 working days, driven by LOTO scheduling and forwarder hand-off. Evidence date: 2026-09-22. Limitation: cost slots and per-destination MFN duty are UNCERTAIN — lookup required at the named customs portal for HS 8541.43 before any shipment relies on this SOP.

Why this process exists

On the CN→LATAM corridor, a DC-string-reverse can be triggered by a pre-shipment inspection finding, a warranty inspection at the LATAM-side warehouse, or a re-export step where the lot is being routed onward to a third country. The objective is to reverse polarity, re-sequence, or re-string a PV array in a controlled, documented way so that the shipment keeps its commercial invoice, packing list, and any electrical certification intact. The reverse must not be confused with a module-level repair; it is a string-level circuit action carried out by qualified personnel.

Disclaimer. Values, codes, and duties shown as UNCERTAIN are placeholders for lookup. The reference equipment family (Jinko Tiger Neo JKM-N-54HL4R-V) is used as a worked example; substitute the actual SKU from the lot's packing list before applying the torque, isolation, or test values operationally.

Step-sequence table

Document checklist

• scope-memo-CN-LATAM-R14.docx
• module-sku-list-packing-list.csv
• oem-datasheet-pack/<sku>.pdf (one per module SKU; example: Jinko JKM-N-54HL4R-V datasheet)
• staubli-mc4-evo-2-installation-manual-MA231-rev-current.pdf
• loto-plan-R14.pdf
• isolation-log-R14.csv
• string-map-template-R14.xlsx
• string-map-annotated-R14.pdf
• engineering-note-reverse-R14.pdf
• re-string-record-R14.csv (with torque value column = 3.0 Nm)
• iec-62446-1-2016-test-report-R14.pdf
• packing-list-revised-R14.pdf
• commercial-invoice-revised-R14.pdf
• hs-8541-43-lookup-screenshot-<destination>.pdf
• forwarder-receipt-R14.pdf

Timeline table

Indicative cost slots

Costs shown below are indicative slots only. No hard prices are published; figures marked UNCERTAIN require a sourced lookup before use.

HS / duty block

HS code, regional duty, and any anti-dumping or safeguard measure on top of MFN must be confirmed against the named customs source for the destination country. Values below are PENDING lookup.

Disclaimer. HS subheading 8541.43 is a common default for photovoltaic cells and modules, but the exact classification, duty rate, and any trade-remedy measure must be confirmed against the official customs portal of the destination country before any shipment relies on it. TradVolt is not a customs authority and this block is not a ruling.

FAQ

1. What counts as a DC-string-reverse?

It is a string-level circuit action in a PV array, typically a polarity reversal or a re-sequence of modules within a string, executed for inspection, warranty, or re-export reasons. It is not the same as a module-level repair.

2. Who is allowed to do the reverse?

A qualified PV site electrician should carry out the physical action. A QA engineer should hold the documentation and the re-test record. Trade-ops owns the customs and shipping documents.

3. Does the reverse affect the commercial invoice or packing list?

Yes. The packing list and the commercial invoice must be re-issued with the new string map and any re-test values before the lot leaves the warehouse, so that customs and the LATAM-side nominated forwarder see a consistent record.

4. How long does the full process take?

The indicative window from booking to LATAM-side receipt is 7 to 10 working days, depending on site access, LOTO scheduling, and forwarder hand-off. See the timeline table.

5. Are costs fixed on this page?

No. Every cost slot on this page is marked indicative and UNCERTAIN (model assumption). Confirm against a named source before using any figure operationally.

Call to action

For a sourced RFQ on the CN→LATAM corridor with a DC-string-reverse step, use the RFQ form.

Request a sourced RFQ for CN→LATAM DC-string-reverse

Claims & sources

Every factual claim on this page maps to a specific source row below. URLs are the official document/product/portal pages used; no internal placeholder filenames are cited as evidence.