A Low-Current Arc Touching an Insulation Barrier in the Contact Gap

The case of a low-current arc interacting with an insulation surface is of special interest for switching technology because of low arc mobility in a self-created magnetic field. The results of an analytical and experimental investigation of the insulation barrier´s damage in the contact zone due to a low-current arc on the surface are reported. Both the arc and the arc-track shapes are estimated as well as the propagating depth of the transformed and ablated insulation layers. In addition, calorimetric measurements of the energy exchange between the arc and the barrier are presented. The propagation power flow is estimated as a value of 5-6 MW/m². An approximate analytical approach is discussed using some of the experimentally estimated data. The main result is the recommended time limit for the interaction between a low-current arc and an insulation barrier.