To investigate the damping effect of a lead damper on ultrahigh voltage (UHV) interconnected electrical equipment, we carried out a shaking table test on an interconnected coupling system comprising a UHV arrester and a capacitor voltage transformer. The equipment frequency and the strain and acceleration of some key components were measured using white noise sweep, seismic test, and damping test. The test results show that the maximum strain response of the arrester is larger than that of the transformer. The arrester of the interconnected coupling system is a vulnerable device. With dampers added, the frequency of the interconnected equipment slightly decreases; thus, the dampers cannot affect the normal operation of the electrical equipment. The top acceleration response and maximum strain response for the arrester and transformer device of the coupling system after adding dampers are greatly reduced under the action of seismic waves with large peak acceleration. The damping efficiencies of the maximum strain response for the arrester and transformer are 75% and 50%, respectively, and the damping effect is significant. The application of dampers greatly enhances the seismic capacity of the interconnected coupling system.