How are leakage currents measured in the IT network?
Subject: SECUTEST SII + / SIII +
Due to technical reasons, a leakage current measurement in the IT network can only be carried out with the replacement device leakage current measurement. In measurements according to the differential current method or the direct leakage current measurement, you will usually only measure currents of a few μA, due to the galvanic isolation of the supply.
The great advantage of the IT network is precisely that any leakage currents that may occur do not pose a risk because the current can not flow.
The replacement leakage current measurement requires no connection to the protective conductor for testing because the test voltage and the protective conductor are generated galvanically isolated from the supply network. The tester forms its own TN network, so to speak. Therefore, this method is the best method for measuring the leakage current in IT networks.
The disadvantage is that the replacement device leakage current measurement does not work with electronically switched test objects, since the load capacity of the test voltage is usually not sufficient to take a consumer into operation. Such devices can only be tested in a TT or TN network.