Shell Products

Shell Diala S3 ZX-I


Shell Diala S3 ZX-I is a state-of-the-art, inhibited electrical insulating oil. It is manufactured from specially refined mineral oils and has an ultra-low sulphur content and long-life characteristics. In addition, it is widely recognised and approved by leading equipment manufacturers as being non corrosive to copper and not requiring a copper passivator, as proved in the latest and most severe copper corrosion tests. It also has good low-temperature properties, which are vital for efficient heat transfer inside the transformer, even at low temperatures.

Designed to protect

Protecting components from damage can help to increase service life and maximise your return on investment in equipment. Shell Diala S3 ZX-I provides continuing transformer protection in service and is intrinsically non-corrosive owing to its low-sulphur base oil. In industry-standard tests, it typically

  • produces less than 20% of the maximum specified limit for sludge
  • has less than 6% of the maximum sulphur limit.

Designed for long oil life

Inhibited oils such as Shell Diala S3 ZX-I contain small amounts of additives to inhibit oxidation and thus prolong their life. The industrystandard test for inhibited oils is 500 hours – three times longer than for uninhibited oils. In addition, Shell Diala S3 ZX-I typically has

  • a dielectric dissipation factor (DDF) after the IEC test that is 20% of the permitted maximum for the higher oxidation test according to Section 7.1 in IEC 60296.

Designed for SYSTEM efficiency

Shell Diala S3 ZX-I is designed to help maximise effectiveness by helping equipment to meet or exceed its design capabilities. Compared with the industry minimum requirements, it offers

  • good low-temperature viscosity to provide optimised heat transfer at low temperatures.

Specifications and approvals

Shell Diala S3 ZX-I meets the requirements of the key industry tests and the specifications for most equipment manufacturers and utility companies.

Real-world value delivery

Shell Diala S3 ZX-I is Shell’s premium fully inhibited electrical insulating oil. It is designed to offer exceptional oxidation stability and is formulated from specially refined base oils to give an ultra-low sulphur content.


Whatever your needs or application, we can provide a full range of oils and greases, including synthetic, high-performance products and additional services.