The primary voltage at Location 1 was 7.2 kV phase to ground and testing easily
achieved HIF conditions on the dry test materials. The soil and grass tests immediately
blew the interrupting fuse because of the saturated ground surface condition (low
impedance). The dry sand and gravel sustained the live conductor on the test material
surface for several minutes without blowing the safety fuse. The HIF finally blew the fuse
by creating a low impedance path through the test material.