In a lot of 1930s movies (Frankenstein for example), whenever people use high voltage machinery there is a lot of shorting out and electrical fires in it's operation - was this an actual problem at the time (from the vacuum tubes and such before circuits and circuit breakers), or was this just movie FX?
I know a common nickname in the wwii era for navy radio operators was "sparks" because of the frequency of that phenomenon with routine radio operation.
I think you're probably right that voltages had to be much higher in tube days.