FIRE HAZARD OF LOCAL HEATING OF WIRES AND CABLES OF ELECTRIC NETWORKS AT OVERCURRENTS

With the purpose of development of the new going near the questions of providing of fire-prevention protection of electroenergy objects by a calculation and experimental a way it was shown that at brief flowing in nonpermanent situations by current-carrying installments of the isolated send-offs and cables of electric networks of direct, variable or impulsive overcurrent of high-slay (100 A
mm2 and more) their copper, àluminium or steel tendons and shells in the narrow areas of “hot” longitudinal areas can test the brief intensive local heating, exceeding 1500 °Ñ. Such local brief heating at overcurrents of current-carrying parts of the isolated wires and cables, conditioned the quantized macrolocalization on their “hot” longitudinal areas of drifting lone electrons, can result to electro-thermal local destruction of their conducting tendons (shells), burning of their isolation and sudden appearance in the areas of gasket of cable-explorer products of hearths of fire. Experiments executed on a powerful high-voltage equipment on the electro-thermal brief heating of overcurrent a nonperiodic impulse of temporal form 9 ms
576 ms (at his amplitude 745 A and closeness 370 A
mm2 ) of the zincked steel wire without an isolation by a diameter 1.6 mm was confirmed the results presented on the basis of scientific positions of classic and quantum physics of close calculations of the intensive local heating of this wire in the areas of forming along him of “hot” longitudinal areas. First exposed feature of the electro-thermal brief intensive local heating of current-carrying parts of the isolated wires and cables at considerable current overloads in electric networks with the overcurrent of different peak-temporal parameters, causing appearance in them of closeness of current 100 A
mm2 and more, allows from the new scientifically grounded positions to examine possible reasons of burning of cable-explorer products and origin on the electroenergy objects of sudden fires.