1. In all types of faults, hydrogen is always present.

2. Low energy faults, such as corona partial discharges in gas bubbles, or low temperature hot spots, will form mainly H2 and CH4.

3. Faults of higher temperature are necessary to form large quantities of C2H4.

4. Faults with a very high energy content, such as in electrical arcs, to form large amounts of C2H2.

5. Arcing is the most concerning type of fault condition as it typically escalates to a transformer failure.