Influence of arc current on fraction Kp of electric arc energy leading to pressure rise in a closed container

When determining overpressure in electrical installations due to internal arcing, it is crucial to know the values of arc voltage and the portion of arc energy leading to pressure rise. In this contribution the fraction Kp of electric arc energy leading to pressure rise in its air surroundings is determined in dependence on arc current, arc energy and electrode material for an arc occurring in a closed container. When the arc current and electric arc energy increases, Kp decreases some-what in the case of copper electrodes and increases in the case of iron and aluminium electrodes. These results are considered to be due to the change in energy balance in the closed container in cases where the arc current and electric arc energy increase.