Hi, Interesting situation. I have some experience with this situation in NZ – mainly in HV generation and distribution stations. It is suggested that the outcome and the problems experienced could be related to: 1. Whether aseismic blocking units had been fitted – these are often used to prevent mal operation of Buchholz protection on transformers. 2. The centre of gravity and positioning of items in panels – as you have indicated. Mounting of heavy auxiliary CTs etc has a direct effect. 3. Seismic restraint of the panels. Control and relay panels are often supported at the top in addition to suitable mounting of the base of the panels to reduce the likelihood of swaying or tipping during earthquakes. Regards, PC