A cable grommet system for installation in data centers, offices and the like, for sealing cable openings in raised flooring, wall or ceiling panels, server cabinets, etc. to facilitate the installation and revision of wiring and cabling to server installations while minimizing losses of any provided conditioned air. A wide variety of grommet configurations is possible with a limited number of component parts. An advantageous acute angle mounting of sealing brushes enhances the sealing effectiveness thereof, particularly for smaller sizes of cable openings. In some embodiments, a novel arrangement of electrical conductors is incorporated into the grommet structures for dissipation of electrostatic charges, enabling the basic frame components to be formed of a flame retardant material.