Abstract: An antiseismic static electrical converter installation comprises a valve assembly mounted on a platform, the platform being suspended at each of two opposite ends from a series of rods which are attached in a spaced-out relationship to a horizontal beam, the beam being mounted on the ground via rubber springs. During an earthquakes movement of the ground causes mainly lateral distortion of the rubber springs and elastic bending of the rods, and, since the natural resonant frequency of the suspension system is designed to be low and the rubber springs are deigned to have significant damping, a high degree of isolation is provided for the platform and the equipment mounted on it. During severe earthquakes, the rods are arranged to suffer a plastic bending which causes them to act like pendulums and changes the natural frequency of the suspension system to increase the damping and provide greater protection.