To XNOX_Rambo,
I think that the author to whom you cited kept in mind more scientific than practical definition of re-igniting. Even for 50 Hz systems ionization still exist long enough after zero-crossing and when applied voltage exceeds ionization level (say roughly 65 V) the arc will be self-supportive again. Usually there is more than enough time. By the way, arc extinguishing problem mostly exist when we turn off the circuit, not when we turn it on. Actually arc may be self-supportive for long time, sometimes seconds. When I immigrated in 1991 it was impossible to find engineering job and I worked as welder for several months, just recall what I studied when was young and used this skills again. So, I know all this stuff in practice. Now welding machines and processes is one of my areas of consulting, but most of the time I work with spot-welding problems. Sometimes I use the arc welding in my RF and microwave works to weld thermocouples or some parts together when welding is more preferable as soldering. But I use special tiny electrodes for this work.
To echo47,
Thanks a lot. The picture is very real. I saw such cases a few times when I was electrical college student and we went through our practice with power plants and distribution centers. Such arching can be very dangerous and may destroy electrical equipment quickly.