4.2 Test transformerThe use of a te

4.2 Test transformerThe use of a test transformer for isolation is optional. For maximum safety, a test transformer for isolation (T2 in Figure 2, T in Figure 6 to Figure 14) shall be used and the main protective earthing terminal of the equipment under test earthed. Any capacitive leakage in the transformer shall then be taken into account.As an alternative to earthing the equipment under test, the test transformer secondary and the equipment under test shall be left floating (not earthed), in which case the capacitive leakage in the test transformer need not be taken into account.