The failure of porcelain cylindrical electrical equipment during earthquakes is a key factor contributing to power supply outages. The meticulous assessment of the seismic resistance of these devices is a foundational requirement for accurately gauging the overall seismic robustness of power systems. The judicious choice of the support dynamic magnification coefficient plays a crucial role in precisely appraising the seismic behavior of porcelain cylindrical electrical equipment. In this research, to derive the support dynamic magnification coefficients for these devices, vibration tests were carried out on three main types of porcelain cylindrical electrical installations: in cluding disconnect switches, voltage transformers, and current transformers, all of which were evaluated as integrated units with their respective support structures under various seismic excitations and different peak ground acceleration levels. Based on these empirical results, finite element analysis was used to examine the effect of parameters such as the stiffness of supports on the natural frequencies of the equipment-to-support system configurations. This analysis also included a discussion on how the support dynamic magnification coefficients vary with different periodic characteristics of the equipment-support assembly systems. The study findings indicate that, within the scope of this study, the support dynamic magnification coefficient tends to increase as the combined or overall period of the equipment-support system increases. Notably, when the total system period exceeds T_g, the seismic response of the system remains at a relatively high level, significantly exceeding the reference values set by design spectra and clearly surpassing the conservative 1.2 limit established by present guidelines, thus implying a potential underestimate of safety margins. Therefore, it is proposed that the support dynamic magnification coefficient for porcelain cylindrical electrical equipment should optimally not be less than 2.0, and concurrently, the frequency of the supports should not be belower than 30 Hz to ensure enhanced seismic safety measures.