What best practices apply to transformer oil storage?

Best practice focuses on keeping oil clean, dry, and uncontaminated. Store drums or tanks sealed, labeled by oil type and batch, and protected from rain and temperature cycling that drives condensation. Use dedicated hoses, pumps, and filters for each oil family to avoid cross contamination, especially with PCB suspect oils. Maintain clean sampling points and use desiccant breathers on bulk tanks. Track certificates of analysis and retain samples for reference. Use first in first out rotation, and avoid mixing oils unless compatibility is verified and approved by the transformer manufacturer or utility standards.