IT Make the fault inoffensive by using networks with unearthed neutral system (IT)
This solution consists of treating not the effect but rather the cause, by limiting the fault current to a few mA. In a network with IT unearthed neutral or impedance-earthed neutral, as the fault is not dangerous, there is no need to trip and operation can continue. However, leaving an earth fault on such a network is equivalent to leaving a direct connection between the network and the earth, as before.
A 2nd fault creates a hazardous current that must cause tripping of the same kind as in the earthed TT and TN networks;
This type of network with unearthed neutral is only really advantageous if the real insulation faults are detected as soon as they occur. This is possible using the Vigilohm System range that automatically and immediately detects the faulty feeders, including intermittent faults (users' pet hate).
