A bracket assembly is used to secure a housing to a support structure such as a post, wall or ceiling. The bracket assembly includes an inner bracket, an outer bracket and a connector. The inner bracket is configured to be mounted on the support structure separately from the outer bracket, and the outer bracket is configured to be quickly mounted on the inner bracket. The outer bracket and connector are joined by a ball and socket joint. Angular adjustment of the ball relative to the socket is made prior to mounting of the outer bracket on the inner bracket, and the desired orientation is maintained using a clamping assembly. The bracket assembly includes sealing features that prevent moisture from entering the assembly.