IT Earthing

From Wiki:

"Laboratory rooms, medical facilities, construction sites, repair workshops, mobile electrical installations, and other environments that are supplied via engine-generators where there is an increased risk of insulation faults, often use an IT earthing arrangement supplied from isolation transformers. To mitigate the two-fault issues with IT systems, the isolation transformers should supply only a small number of loads each and/or should be protected with an insulation monitoring device (generally used only by medical or military IT systems, because of cost). "

"increased risk of insulation faults" does it mean this type of system reduced the probability of insulation failure or L-G fault?

The use of iT systems has many advantages relating to other grounding systems.

But care must be exercised to immediately detect the first fault, for the second fault may lead to serious problems.