I haven't seen exothermic connections used for energized conductors, but that could be because you may want to disconnect the ungrounded wires.
But if they exist, ERICO (aka Cadweld) would know about them.
BTW - ERICO stands for Electric Railway Improvement COmpany, which was founded in 1903.

Anyone wanting to see a cool way to install wire terminals is invited to check out https://www.youtube.com/watch?v=KuMkQxdn7OA.


Ghost307