So we have this electrical control panel in which we have a 24v dc and a 24v ac circuit both. The 24v ac is coming out of a 400/24v transformer. The transformer primary is being fed from a 3-phase 400v (L-L) supply and the secondary of the transformer is 24v ac and is isolated from the ground which means there's no neutral and both of the secondary terminals would be considered live/hot. When i measure the voltage across these two secondary terminals i get 24v ac. Makes sense but if i measure the voltage across either of the two secondary terminals with respect to the ground i get 230v ac on the meter. Why is that? Also, if i measure AC voltage across the 24v DC circuit with respect to ground i get 230v AC there too. This is confusing. What do you make of it?
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\$\begingroup\$ Perhaps your AC voltmeter has a very high internal resistance - some are 10 million ohms. \$\endgroup\$– glen_geekCommented Feb 27 at 13:37
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It's simply parasitic capacitance between primary and secondary winding. Try making the same measurement with a 100 kohm resistor in parallel with the meter.
