Post-Import Installation, Assembly and Technical Assistance in Turkish Customs Value: Article 28 (2026)
Short and Clear Answer
Customs Law No. 4458 Article 28 excludes qualifying charges for construction, erection, assembly, maintenance or technical assistance undertaken after importation for imported goods such as industrial plants, machinery or equipment, provided the charges are distinguishable from the price actually paid or payable. The exclusion applies because post-import work is not part of the imported goods value when the statutory conditions are met.
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A turnkey contract does not automatically make the entire project price customs value, and a separate service invoice does not automatically prove exclusion. The importer must show what work is performed after import, what amount relates to that work and how the amount is separated from the goods price. Foreign EPC contractors and machinery suppliers should structure contracts and invoices so the Article 28 distinction can be proven.
Article 28 separates qualifying post-import work from the customs value of imported machinery and equipment.
Contents
1. Article 28 Creates a Specific Exclusion for Qualifying Post-Import Work
Transaction value under Article 24 begins with the price actually paid or payable and is adjusted under Articles 27 and 28. Article 28 states that specified charges for construction, erection, assembly, maintenance or technical assistance undertaken after importation are not included in customs value when they are distinguished from the price.
The rule is highly relevant to imports of production lines, industrial robots, turbines, medical equipment, machine tools, packaging lines and other complex equipment that requires on-site work in Turkey after arrival.
The exclusion is not an exemption from customs duty. It defines what is outside the customs value of the imported goods. The legal analysis therefore focuses on timing, nature of the service and documentary separation.
2. Construction, Erection, Assembly, Maintenance and Technical Assistance
The Ministry of Trade customs-value guidance expressly lists post-import construction, erection, assembly, maintenance and technical assistance for imported industrial plants, machinery and equipment. Each category describes work performed after the goods have entered the relevant customs territory.
Assembly includes putting imported components or machinery together at the Turkish site. Erection can include positioning and installing large equipment. Technical assistance can include commissioning support, calibration, testing and specialist intervention after import where the service falls within the statutory rule.
Maintenance includes qualifying post-import maintenance charges when they are distinguishable. The importer must separate these services from the purchase price rather than assume every service connected with machinery is excluded.
3. The Work Must Be Undertaken After Importation
Timing is fundamental. Article 28 addresses work undertaken after importation. Engineering or manufacturing work performed abroad before shipment can be part of the goods value or, in some cases, an Article 27 assist if supplied by the buyer. Those costs are not converted into post-import services by invoicing them later.
Project records should identify when each service was performed. Installation reports, technician timesheets, site-entry records, commissioning certificates and acceptance protocols can establish that the work took place in Turkey after importation.
Mixed service contracts should split pre-shipment factory services from post-import site services. A single undifferentiated engineering fee creates a valuation risk because customs cannot verify the Article 28 portion.
4. The Charge Must Be Separately Distinguished
The statutory exclusion depends on the amount being distinguishable from the price actually paid or payable. The strongest evidence is a contract that allocates separate prices to goods, installation, commissioning and maintenance, followed by invoices matching that allocation.
Separate invoicing is helpful but substance remains decisive. If the goods invoice is artificially reduced and the service invoice includes part of the equipment price, customs can examine the real consideration under Article 24. Conversely, a single invoice does not necessarily destroy the exclusion if the qualifying post-import amount can be objectively and verifiably separated.
Allocation should be agreed before shipment. An after-the-fact percentage created only when customs questions the value is less persuasive than contemporaneous project costing.
5. Turnkey and EPC Contracts Require Component Pricing
Turnkey projects often combine design, equipment supply, overseas freight, civil works, installation, commissioning, training and warranty support. Customs value applies to imported goods and the legally relevant additions; it does not automatically equal the total project price.
The project contract should identify imported equipment packages and post-import services. Milestone payments should be mapped to those components. If one advance covers both goods and services, the accounting schedule should show how it is allocated.
Foreign EPC contractors should coordinate customs valuation with the Turkish importer before the first shipment. Waiting until final acceptance can leave dozens of import declarations based on an incomplete allocation.
6. Engineering and Supervision Need a Location-and-Function Analysis
Engineering work can fall into different customs categories. Buyer-supplied engineering and design undertaken outside Turkey and necessary for production can be an Article 27 assist. Post-import technical assistance undertaken in Turkey can fall within Article 28 when its conditions are met.
The importer should therefore identify where the engineering work was performed, whether it relates to manufacturing the imported goods or to installing them after arrival, and how the fee is calculated.
Site supervision by foreign engineers after import should be supported by work scopes, travel records and timesheets. Remote engineering performed abroad requires its own classification rather than being included automatically in the post-import exclusion.
7. Warranty, Preventive Maintenance and Service Packages
Machinery contracts often include a warranty period and optional maintenance package. The customs treatment depends on what is included in the goods price and what is a separately priced post-import service.
A free warranty embedded in the sale price is not automatically deducted from the transaction value. The importer cannot create an Article 28 deduction merely by estimating what the warranty might be worth. A separately agreed and distinguishable qualifying maintenance service is different.
Extended maintenance contracts concluded separately after import should be preserved in the customs file to demonstrate their timing and independence from the sale where relevant.
8. Technician Travel, Accommodation and Site Expenses
Installation invoices can include technician travel, accommodation, per diem and local transport. These amounts must be analyzed as part of the qualifying post-import service package when they are genuinely connected with work performed after import.
The contract should state whether such costs are included in a fixed service price or reimbursed separately. Receipts and travel records support the nature and timing of the work.
Costs incurred before import for factory acceptance testing or pre-shipment engineering should not be mixed with post-import site expenses. The customs worksheet should keep the two phases separate.
9. Advance Payments Do Not Determine the Customs Category
A buyer may pay 30% of a turnkey contract before production, 60% on shipment and 10% after commissioning. Payment timing does not determine whether an amount is goods value or post-import service value.
The legal classification follows what the payment is for. The importer should allocate advances according to the contract’s goods and service components and reconcile the allocation to final invoices.
Where an advance is non-refundable and covers several obligations, project accounting must still establish the portion attributable to the imported goods and the portion attributable to qualifying post-import work.
10. Documents Needed to Defend the Article 28 Exclusion
Keep the turnkey or sales contract, price schedule, commercial invoices, service invoices, milestone-payment table, installation reports, commissioning certificate, technician timesheets, travel documents, site acceptance records and accounting allocation.
Where the project uses several customs declarations, maintain a schedule connecting equipment values to each declaration and showing that excluded services were not embedded in the declared goods value.
Customs Law Article 11 permits document requests; Article 13 governs record retention. Foreign contractors should commit contractually to provide technical and project records needed by the Turkish importer.
11. Understatement and Overstatement Have Different Remedies
If a company wrongly excludes an amount that is actually part of customs value, Article 234(1)(b) can apply to the resulting deficient value, requiring the duty difference and a fine equal to three times that difference when its elements are present.
If the importer includes a qualifying Article 28 service and overpays customs duty, the company should assess the statutory correction and repayment framework instead of leaving the inflated value unchallenged.
Customs decisions and penalties can be challenged under Article 242 within fifteen days from notification. The objection should identify the post-import service, timing, separate price and supporting documents.
Official and Related Sources
- Ministry of Trade – Customs Value FAQ
- Customs Law No. 4458
- Freight and Insurance in Turkish Customs Value
Frequently Asked Questions
Is post-import installation included in Turkish customs value?
Qualifying post-import installation is excluded under Article 28 when the statutory requirements are met and the charge is distinguishable.
Does a separate invoice automatically prove exclusion?
No. The invoice helps, but the service must genuinely fall within Article 28 and the amount must be supportable.
Are turnkey contracts fully dutiable?
No. The imported goods and legally relevant additions form customs value; qualifying post-import services can be outside it.
Can commissioning be excluded?
Qualifying post-import technical assistance and commissioning work is analyzed under Article 28.
What about engineering performed abroad before shipment?
It requires a separate customs analysis and is not converted into post-import work merely because it is billed later.
Can maintenance be excluded?
Qualifying post-import maintenance charges are within Article 28 when the statutory conditions are met.
What penalty applies to an improper exclusion?
Article 234(1)(b) applies to deficient customs value when its elements are present.
What is the objection period?
Article 242 provides fifteen days from notification.
Lawyer Review and E-E-A-T
Prepared by: Attorney Halil BAKIRCI – Mersin Bar Association, Registration No. 3472
Legal review: Bakırcı & Keskin Law Office.
This guide was reviewed against Customs Law No. 4458 Articles 11, 13, 24, 27, 28, 234 and 242 and the Ministry of Trade’s customs-value guidance.
Contact Us About Machinery Customs Valuation
Last legal-source review: 12 September 2026.
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