RSA Backplane and Chassis Assemblies for Photonic Service Switches Held Classifiable Under Tariff Item 8517 79 90 with Nil Basic Customs Duty — CAAR Mumbai

1. Background and Nature of the Application

The Customs Authority for Advance Rulings (CAAR), Mumbai, delivered a ruling in the matter of In re Sanmina-SCI India Private Limited, addressing two interconnected customs classification questions: first, whether RSA Backplane and Chassis Assemblies imported for use in manufacturing photonic service switches fall under Customs Tariff Item 8517 79 90; and second, whether such imports qualify for the Nil Basic Customs Duty (BCD) rate under Serial No. 5 of Notification No. 57/2017-Customs dated 30.06.2017, as amended.

The applicant, M/s. Sanmina-SCI India Private Limited (IEC No. 0403030714), filed its application (CAAR-1) at the secretariat of CAAR Mumbai on 13.05.2026 under Section 28H(1) of the Customs Act, 1962. The company is an electronic contract manufacturer incorporated in India, functioning as a joint venture between Reliance Strategic Business Ventures Limited and Sanmina-SCI Systems Singapore Pte. Ltd. The Sanmina Group operates across 21 countries on six continents and is among the world's largest providers of electronic manufacturing services.

The advance ruling was sought in respect of three specific product models:

  • RSA Backplane and Chassis Assembly PSS-8x — LFIALC3TD00071AAAC
  • RSA Backplane and Chassis Assembly PSS-12x — LFIALC3TD00286AAAC
  • RSA Backplane and Chassis Assembly PSS-24x — LFIALC3KC50378ABAC

The applicant confirmed that no proceedings involving the same issue were pending before any customs authority, appellate tribunal, or court, rendering the application admissible under Section 28-I(2) of the Customs Act, 1962.

2. What Are the Imported Goods?

(i) Physical and Material Composition

The three RSA Backplane and Chassis Assemblies are fabricated from aluminium and pre-plated steel, with an integrated backplane Printed Circuit Board Assembly (PCBA) forming an intrinsic part of each unit. The pre-plating process — which may involve zinc, nickel, chromium, or tin coatings — is not a cosmetic addition but serves multiple technical purposes: corrosion resistance, uniform thermal conductivity, electromagnetic shielding effectiveness, and consistent surface properties that eliminate the need for post-manufacture treatments.

The chassis structures are manufactured to comply with ISO 1302-2002 dimensional and surface finish standards. They are produced by overseas suppliers strictly in accordance with designs, drawings, and specifications furnished by the applicant, making each assembly a bespoke product tied to a particular model of photonic service switch.

(ii) Structural and Functional Architecture

Each assembly performs several simultaneous roles within the photonic service switch:

Mechanical hosting and structural integrity: The chassis provides a precisely engineered enclosure with demarcated protrusions, compartments, bounded chambers, and mounting pads that align exactly with the interface cards, power supply modules, fan assemblies, and processor cards inserted into the switch. The high-precision fit ensures that no translational or rotational displacement of inserted cards can occur due to vibration, thermal expansion, or mechanical stress during the operational lifecycle of the switch.

High-speed data interconnection via the backplane PCBA: The integrated backplane PCBA contains carefully engineered signal traces, high-speed connectors, and embedded switching and bridging circuits. These collectively support a non-blocking switching capacity of up to 24 Tb/s in the 24-slot configuration, allowing any interface card to exchange data with any other across the backplane without signal bottlenecks, attenuation, or phase distortion.

Power distribution: The backplane PCBA incorporates dedicated power buses and power-pin connector groups that route stable DC power from the power supply units to each interface card, control card, cooling assembly, and other active module housed in the chassis, ensuring uninterrupted operation across the platform.

Control, management, and synchronisation signalling: Through specific connector pins and dedicated PCB traces, the backplane implements a management and control plane that distributes clock signals for timing synchronisation, configuration and monitoring channels, and fault detection and error-reporting pathways between modules and the system controller.

EMI and RFI shielding: The pre-plated steel chassis and covers act as an electromagnetic barrier, preventing external electromagnetic interference from penetrating the enclosure and disrupting the sensitive electronic components of the switch. Conductive coatings on the steel absorb and reflect electromagnetic waves, while internal partitions and demarcated chambers further reduce crosstalk between adjacent interface cards.