Protection against fire due to earth faults
From Electrical Installation Guide
The standards consider the damage (mainly fire) of goods due to insulation faults to be high.
Therefore, for location with high risk of fire, 300 mA Residual Current Devices must be used. For the other locations, some standards rely on a technique called " Ground Fault Protection "
ru:Защита имущества от ущерба вследствие пробоя изоляции zh:保护商品免受绝缘故障的危害