What should be checked when purchasing transformer oil for sale?

Check standard compliance, certificates of analysis, batch traceability, and fresh test results for BDV, moisture, acidity, interfacial tension, resistivity, and inhibitor content if applicable. Confirm oil type, viscosity grade, and whether it is inhibited or uninhibited. Verify packaging is sealed, dry, and properly labeled, and confirm storage and transport conditions prevent moisture ingress. For retrofill or topping up, confirm compatibility with existing oil and insulating materials. Also confirm SDS availability and disposal guidance for any contaminated packaging.