Electric arcs in open air

A summary of the phenomena associated with unconstricted arcs burning in open air in the current range 0.1 A to 20 kA is presented. Detailed current-voltage characteristics are given for electrode separations from 5 to 500 mm, together with an analysis of the temporal behaviour for both convection and magnetically influenced arcs. The results should provide useful information for the prediction of the effects of arcing short circuits of various kinds.