Electrical fault phenomena are diverse, for example, the same type of fault may have different fault phenomena, different types of fault may be the same fault phenomenon, the identity and diversity of this fault phenomenon, to find the fault has brought complexity. However, the fault phenomenon is the basic basis for finding electrical faults, is the starting point for finding electrical faults, so it is necessary to carefully observe and analyze the fault phenomenon, find out the most important and most typical aspects of the fault phenomenon, and understand the time, place, and environment of the fault.

1. Direct perception

Some electrical faults can be directly perceived by the abnormal temperature rise, vibration, odor, sound, color change, etc. of the faulty equipment through the human hand, eye, nose, ear and other organs, using the touch, see, smell, and listen to determine the fault part of the equipment.

2. Instrument testing