There is no agreement within the utility industry on how often HIFs occur. Many relay engineers perceive that the number of HIFs are a small percent of all faults. Line crews generally state that a much larger percentage are not cleared by conventional overcurrent protection. Relay engineers typically make their judgements based on trouble reports, which tend not to include all downed conductor events. The field observations by line crews are probably closer to fact, but little data has been kept on HIFs. Utilities typically don't record an event unless it results in a breaker or fuse operation. Over an eleven year period, researchers at Texas A&M University staged over 200 high impedance faults at five utilities and on ten distribution feeders. Of these 200, only 35 were cleared by conventional protection. Clearly, for the type of fault that falls into the HIF category, the operation of conventional protection (and hence our ability to count the event) is not a good indicator of the number of HIF events. For example, re-energizing a line with a broken conductor may creat a high impedance fault. The need for better data is evident for utilities considering the use of HIF detection. Some of the factors affecting the number of HIFs that occur are: voltage level, type of construction, and age of the circuit.