As my colleagues have stated. Ungrounded systems are fraught with hazards. It is far more common to find that industrial sites are using resistive or impedance grounded systems. The have the advantage of tolerating ground faults long enough to isolate them and fix them without all the voltage and insulation issues associated with a ground fault on an ungrounded system.
In Canada our industrial voltage is 600 instead of 480 which puts even more stress on an ungrounded system. in normal operation a balanced 600 volt delta service floats around 347 volts to ground but if any phase grounds the voltage is now 600 in the other 2 ungrounded conductors which puts a bigger stress on all the components and insulation.
