Lubricant test method

A method of determining the compatibility of a lubricating fluid such as engine oil with an energized electrical component comprises; contacting a test apparatus 1 with the fluid, applying an electrical current to the test apparatus, and monitoring the current flow through the test apparatus over time. The test apparatus includes at least one pair of conductors 2 separated by an insulator 4 that does not extend across the whole of the opposing surfaces of the conductors. The electrical current is applied across the pair of conductors where the fluid penetrates between them.