How to Source a Transformer
from China

1 Define Your Technical Specification

Before contacting any manufacturer, prepare a clear technical specification. At minimum you need:

• Rated capacity — kVA or MVA
• Primary (high) voltage — kV — e.g. 11 kV, 33 kV, 132 kV
• Secondary (low) voltage — V or kV — e.g. 400 V, 11 kV
• Frequency — 50 Hz or 60 Hz
• Standard — IEC 60076, ANSI/IEEE C57.12, GB/T 1094, or customer spec
• Cooling method — ONAN, ONAF, OFAF — or leave open for recommendation
• Vector group — e.g. Dyn11 for IEC distribution, Dyn1 for ANSI
• Quantity — Number of units
• Installation site — Country, altitude, ambient temperature range

The more detail you provide upfront, the more accurate and comparable the quotes you receive will be. Vague enquiries result in vague offers.

2 Verify the Manufacturer — Not Just the Trader

China's transformer supply chain includes both actual manufacturers and trading companies that source from factories. For quality control and price efficiency, working directly with a manufacturer is preferable. Key checks:

• Ask for factory photos — production floor, winding machines, testing bay
• Request type test reports from a third-party accredited laboratory
• Check if they have an in-house electrical test bay for routine tests
• Ask about production capacity — annual output in units
• Request customer references from your region if possible
• Verify they manufacture your product type in-house (not sub-contracted)

3 Understand the Quote Components

A proper quote from a Chinese transformer manufacturer should include:

4 Quality Assurance During Production

For significant orders, consider arranging third-party inspection or factory acceptance testing (FAT) before shipment. Options include:

• Routine test witnessed by your representative or a third-party inspector (SGS, Bureau Veritas, Intertek)
• Pre-shipment inspection of packing, nameplate data, and visual condition
• Review of routine test report before releasing payment balance
• Factory visit if ordering multiple units or starting a long-term supply relationship

5 Export Documentation for Customs Clearance

Standard export documents required for most countries include:

• Commercial invoice (with HS code — typically 8504.21 or 8504.22 for transformers)
• Packing list (dimensions, weights, number of packages)
• Certificate of origin (CO) — for preferential duty rates where applicable
• Bill of lading (sea freight) or airway bill (air freight)
• Routine test report — required by many utility acceptance teams
• Nameplate data sheet — rated values, serial numbers, year of manufacture