The present invention is directed to electrical connectors of the industrial type, as opposed to typical household electrical connectors. In their most usual form, industrial connectors are provided in the form of a cooperating male and female pair. The male connector comprises a male contact mounted within an insulative housing. The rearward end of the male contact is provided with means by which it may be connected to a cable or a bus bar. The female connector comprises a female contact mounted in an insulative housing. The female contact is provided with a rearward end with means by which it may be connected to a cable or bus bar. When the cooperating pair of connectors is in its mated or connected condition, the male contact is received within the female contact and a portion of the insulative housing of one of the connectors is received within a portion of the insulative housing of the other, so that the male and female contacts are totally enclosed. Frequently such industrial connectors are provided with means to retain or lock them in their mated or connected condition. In many instances, the insulative housings of industrial connectors are made entirely of elastomeric compounds or epoxy materials. In other instances, they comprise metallic members filled with insulative elastomeric material or epoxy material.
The use of industrial cable connectors in nuclear environments, such as are encountered in nuclear generating station,, has heretofore been largely avoided even though they would constitute a great convenience from the standpoint of replacement and repair of various types of electrical equipment. This is true for a number of reasons. Under normal conditions, electrical connectors in such an environment can be subjected to high doses of radiation, considerable heat and moisture. In the event of a LOCA (loss of coolant accident), the connectors would be subjected to additional radiation, temperatures as high as 350.degree. F., as well as moisture, some in the form of steam. The moisture frequently would contain such materials as sodium nitrate or boron, rendering it even more corrosive.
Over long periods of time, ordinary elastomers tend to continue to cross link, ultimately destroying themselves, becoming hard and brittle. Under conditions of radiation and/or elevated temperatures, ordinary elastomers may have the oils contained therein removed therefrom, resulting in deterioration. Many types of epoxy will tend to shrink or deteriorate due to elevated temperatures and radiation. In connectors containing exterior metallic shells, deterioration of the elastomeric insulative material or shrinking of the epoxy insulative material will destroy the bond between the insulative material and the surrounding metal members as well as the contacts. This bond can be additionally destroyed by oxidation of the metal members. This, in turn, can result in "hosing" of steam and moisture through the connectors and the cables to the electrical equipment to which they are attached, resulting in shut down of such key equipment as fans, pumps and the like, which must be kept running. Therefore, to obviate these problems, most installations in nuclear power plants and the like have been "hard wired", avoiding the use of electrical connectors.
The present invention is directed to industrial electrical cable connectors suitable for use in nuclear environments such as are encountered in nuclear generating plants and the like, and which will function properly even under conditions of a LOCA. The present invention contemplates an electrical connector comprising a male receptacle assembly and a female plug assembly wherein the mateable male and female electrical contacts are surrounded by special elastomeric and/or epoxy compounds resistant to heat, steam and radiation, and capable of maintaining steam and moisture proof integrity to prevent hosing through the cables. The male receptacle assembly and the female plug assembly are provided with metallic shells having uniquely configured interior surfaces to improve bonding between the metal surfaces and the elastomeric or epoxy compounds, and which provide baffles, creating pressure drops if the bond should fail. The same is true of the exterior surfaces of the male and female contacts. This maintains the integrity of the seals for a longer duration. The metallic parts are made of stainless steel or brass. When brass is used, the parts are plated with nickel, chrome or the like to prevent oxidation thereof. The metallic members, when plated, are etched to enhance the bond and prolong the bond life between the metal members and the elastomeric or epoxy compounds. In addition, O-ring seals are provided on the shells to prevent leakage through the faces of the connectors, certain of the O-rings in compression, an at least one O-ring forming a butt seal. The receptacle assembly and the plug assembly may be provided with polarizing keys and keyways to assure proper positioning of the male and female contacts and to enable the male receptacle assembly to be disconnected from the female plug assembly through the use of a pipe wrench or the like, even after years in a corrosive atmosphere. Finally, as will be described hereinafter, two or more special insulating elastomeric or epoxy materials may be used in each of the receptacle assembly and plug assembly, the materials being chosen for their particular properties.