A protective cap for adhesion to a substrate including a substantially flat base sheet, a dome extending outwardly from an obverse side of the base sheet and forming a cavity in the opposite side of the base sheet with the cavity sized for substantially encapsulating a connector. The cap also includes a semi-tubular shield extending outwardly from one side of the base sheet that defines a channel in the opposite side of the base sheet extending from the cavity toward the periphery of the base sheet, and an integrated primer layer comprising a pressure-sensitive adhesive and attached to the reverse side of the base sheet for application to the substrate.