Although it’s rated to 500 V, it violates the fundamental principle of high-voltage electronics debugging:
Always keep one hand in your pocket!
The scorched and truncated probe tip on the “ground wire” shows Phil slipped at least once:
After far too long, I sacrificed a black multimeter probe from the heap, soldered an alligator clip on the end, and, henceforth, will use it appropriately. Mostly, I never do any high-voltage work, but you never know.
I suppose I should splice that nice black probe onto the end of the Beckman wire for low-voltage work…