What standards apply to transformer oil in South Africa?

In South Africa, transformer oil specifications commonly reference local and regional standards alongside IEC style requirements. For example, supplier documentation in the market cites SANS 555 and utility related specifications such as NRS 079 1 for insulating oil requirements and testing expectations, alongside broader international methods. Actual project requirements depend on the utility, the asset class, and procurement documents, so the governing standard set is confirmed in the tender or maintenance procedure.