Hmm, normally the obligatory RCD should have tripped!
BTW, with normal supply from the energy provider - at least here in Germany- the delivery from external ist T-NCS: Terre -Neutre Combiné-Separeé: 4-conductors (Earth and Neutral Combined) up to the user distribution, here bridge to local earth (Building [basement], water pipes, gas pipes etc.), than 5-conductors after the RCD. This way there should be no real difference between Neutral and Earth concerning noise etc., as long as the RCD didn't trip.
Dr. H. Backhausen
Biting the hand that feeds IT
