At the scene of the traffic collision, Supergirl's path is blocked by a fallen electricity cable that appears to be live as it is sparking and dancing around. She grabs the cable and snaps it which 'kills it'.
Live wires do not spark and dance, and snapping the cable would have no effect; That's not how electricity works.
When Supergirl kicks Reaction, her kick does not connect yet Reaction still flies away from the kick.