Soldato
Found this linked on another site, shocking
penski said:Saw that a while back...Still can't decide if it's genuine or not :/
*n
This is probably normal for opening a switch with that much voltage across it. As the switch first swings open, the gap is very small and the voltage makes an arc as it breaks down the air (turning it from an insulator to a conductor.) Once this arc is established it grows in length as the switch is opened further since most of the air between the switch contacts has already been rendered conductive. Notice that the arc rises as time goes by because the arc heats the air and hot air goes up. The arc goes through the longer path because that hot air that is rising is still more conductive than the cold air down below which replaces it. Eventually the conductive air rises enough that the path through it has to also go through the colder non conductive air and this breaks the arc.
Evil-Penguin said:That sort of only happens when it's opened under load, which shouldn't be done really as it can wear down the contacts. I think I remember reading somewhere that it was caused by a fault, but I thought most switches were submersed in oil anyway.