This paper presents the electric field analysis as well as the experimental verifications of a silicone rubber insulator by considering DC and AC voltage conditions. As a first step, a 3D electric field simulation of the insulator was performed by using a commercially available software based on finite element method. DC voltage and 50 Hz power-frequency voltage simulations were conducted for the given insulator. Low frequency field distribution along the insulator has been investigated to find threshold frequency values for resistive and capacitive field regions. The effect of the conductivity of air surrounding the insulating system on the electric field was evaluated. For each condition, electric potential and field distribution along the creepage path of the insulator was obtained. In addition to the simulation studies, voltage measurements under AC and DC conditions utilizing a different approach for the silicone rubber insulators were conducted on the insulator by using a non-contact type electrostatic voltmeter to validate the simulation results.