PURPOSE: To support a main body of the heavy-duty electrical equipment against an earth-quake by a method wherein a sliding device is installed between the main body of the heavy-duty electrical equipment and its installation base.

CONSTITUTION: Main body of the heavy-duty electrical equipment such as a transformer 3 etc. is installed on the installation base 1 via a sliding device having a low resistance such as a roller bearing 2 etc. The sliding direction of the roller bearing 2 is set at a right angle with respect to a plate plane of the inner core composed of piled layers in the transformer 3. If desired, both side of the trasformer 3 are connected to the stopper 6 via spring 5. Thereby, when the foundation 1 is vibrated in a direction of sliding of the roller bearing 2, its horizontal sliding is not transmitted to the transformer 3. Therefore, a rate of response against the main body at the foot of the insulator glass 4 at the head of the transformer 3 is kept less than 1, resulting in no resonance phenomeum in it.