Electrical assemblies used in outdoor environments, such as outdoor sound, display, and light assemblies are exposed to environmental elements including sunlight, wind, rain, ice, salt, snow, mud, and the like. Internal components and electrical circuits of the electrical assemblies are susceptible to damage if not protected from exposure to the elements. Electronic assemblies that will be used outdoors or in other harsh environments are typically constructed to define a substantially sealed cavity to protect the internal components from the elements.
Electronic assemblies are also exposed to thermal cycles, such as during day and night use, sun and shade, summer and winter, and when powered on and off. Thermal cycles can change the pressure within the enclosure of the light assembly, and the resulting pressure cycles within the enclosure can draw and/or wick moisture past many types of existing seals and gaskets and into the enclosure. Moisture can be drawn into an otherwise sealed enclosure along the inside of a jacketed wire.
One common example of electronic assemblies that are routinely exposed to harsh environmental condition are light assemblies employed on emergency response vehicles and vehicles conducting roadside operations such as DOT and tow trucks. Electronic assemblies include a plurality of wires that penetrate the assembly housing to deliver control signals and/or power. The wires require a seal where they pass through the assembly housing so that moisture cannot reach sensitive components within the assembly. Prior art light assemblies may use methods of sealing such as threading each wire through holes in individual rubber grommets or potting with an epoxy encapsulant that flows around the wires and cures to a hardened state. The process of installing rubber grommets is slow, painstaking, and not easily automated. The epoxy encapsulant does not form a strong bond with, or adhere well to, the jacket of each wire. Further, hardened epoxy cannot move or flow in response to shifting of wires during installation or use. The prior art methods can allow water to pass through the housing inside of a jacketed wire.
There is a need for a seal structure and method that efficiently and effectively seal apertures through which conductors pass into electronic enclosures.