Stating that while the voltage associated with their use was high(usually between 20,000 and 150,000 volts),
the amperage(around 3 Milliamps) was too low to cause any permanent damage.
But when that difference exceeds 5 Milliamps, an indication that a ground fault may be occurring,
the GFCI shuts off the flow in an instant- as little as .025 second.