Systems and methods for providing seals around the motor leads and other conductors in ESP's. In one embodiment, elastomeric boot seals are positioned within annular spaces around motor leads in an ESP motor. When the motor is filled with dielectric oil, the elastomeric material of the boot seals absorbs some of the oil and swells. High temperatures may also cause the material of the seals to expand. Retainers which are not subject to swelling are positioned around the boot seals, thereby preventing the boot seals from expanding away from the leads. The retainers thereby maintain the seal of the boot seals against the motor leads.