Abstract:
A water seal between insulated electrical conductors connected to an underwater device such as a light and the entrance to a conduit containing the conductors is provided. The seal may be installed in existing pools when electrical cable is run through a conduit to the pool or may be installed over existing electrical cable passing through a conduit to a pool by using a split plug. The seal may also be provided by the manufacturer of apparatus for use in pools by forming a plug at a selected position on electrical cable that is attached and sealed to an electrical device such as a light.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    This invention pertains to electrical fixtures in pools. More particularly, a water seal between insulated electrical cable and the interior wall of a conduit leading to an electrical fixture in a pool and methods for use are provided.  
           [0003]    2. Description of Related Art  
           [0004]    Swimming pools and other man-made pools are often lighted with underwater lighting fixtures. Insulated electrical cable from an electrical service box to the fixture is usually run through a conduit made of plastic and is molded or otherwise sealed into the light or other device where the cable containing conductors enters the device. A housing of the fixture forms a niche for the light or other device in the wall of the pool. The housing may not be sealed to prevent water from the pool entering the housing. If the conduit containing the electrical cable and other conductors is not sealed against water entry, water is then confined to the pool by the section of conduit that is placed below the water level in the pool. This conduit is usually laid below a deck or other ground-level surface around a pool, which means that the conduit may extend a considerable distance below the water level in the pool. Such conduits are sometimes damaged during or after construction of a pool, and it is not uncommon for water to leak from a pool through a conduit below ground level. The leak may cause collateral damage to the pool or its surroundings that is expensive to repair.  
           [0005]    In an attempt to seal the end of conduit entering a pool, silicone rubber or putty is sometimes placed around electrical conductors entering the pool. The problems arising from use of such materials are that removal of the electrical conductors or the fixture for repair or replacement then becomes difficult and time-consuming. Also, the seal may not be effective.  
           [0006]    What is needed is an inexpensive, effective seal that may be placed around electrical conductors entering a pool below water level. The plug or seal should be available, for examples, as an integral part of conductors attached to lights or other devices to be used in the new construction or replacement market, for placement around conductors that are being installed, for placement around conductors that are already in place in a conduit, or as a plug to be placed between insulated conductors and a conduit as a replacement part for a plug that failed. 
       
    
    
     DESCRIPTION OF THE FIGURES  
       [0007]    [0007]FIG. 1 shows a cross-section elevation view of an electrical fixture below water level in a pool with a conduit containing insulated electrical conductors and one embodiment of the seal disclosed herein.  
         [0008]    [0008]FIG. 2 shows an embodiment of the seal disclosed herein having a corrugated surface.  
         [0009]    [0009]FIG. 2A shows an embodiment of the seal disclosed herein molded to insulated electrical cables passing therethrough.  
         [0010]    [0010]FIG. 3 shows an embodiment of the split seal disclosed herein having a corrugated surface.  
         [0011]    [0011]FIG. 4 shows an embodiment of the seal disclosed herein having a smooth cylindrical surface with o-ring grooves.  
         [0012]    [0012]FIG. 5 shows an embodiment of the split seal disclosed herein having a smooth cylindrical surface.  
         [0013]    [0013]FIG. 6 shows a sub-assembly of a corrugated seal disclosed herein in the end of a conduit with an adapter attached to the conduit.  
         [0014]    [0014]FIG. 7 shows a sub-assembly of a smooth and tapered cylindrical seal disclosed herein held in place by a cap.  
         [0015]    [0015]FIG. 8 shows a cross-section elevation view of an electrical fixture below water level in a pool with a conduit containing insulated electrical conductors and a second embodiment of the seal disclosed herein. 
     
    
     SUMMARY OF THE INVENTION  
       [0016]    A plug to form a water seal between a conduit and electrical cable passing through the conduit is provided. The plug includes a cylinder and one or more openings through the cylinder for electrical cable. The cylinder and openings are sized so as to form a water seal between the electrical cable and the conduit. The outside surface of the cylinder may be corrugated. The plug may be formed from a deformable material or may be formed from a rigid material with deformable material such as an o-ring used to seal. The cylinder may be split so that it can be installed around cable already present in a conduit.  
         [0017]    In another embodiment, the plug seal is manufactured as part of electrical apparatus. The plug seal may be placed on electrical cable so as to allow easy removal or maintenance of apparatus in a pool. Methods for installing the seal in new or existing applications are provided.  
       DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0018]    Referring to FIG. 1, water  10  is contained in a pool such as a swimming pool or other man-made pool having a wall or side such as side  12 , which may be formed of concrete or other material. Fixture  14  is mounted in wall  12 . Fixture  14  may be a lighting fixture, as shown, or may be any other device employing electrical power or an electrical signal, such as a pump or a controller. In FIG. 1, fixture  14  includes light  16 , which is connected to cable  18  which is formed by insulated electrical conductors. Normally, cable  18  is molded into the base of light  16  so as to electrically insulate the connection between cable  18  and light  16 . An installer normally provides extra loops of cable  18 , shown as  18 A, within housing  24  so as to allow removal of light  16  from fixture  14  and placement of light  16  on deck  13  for repair, such as replacement of a light bulb, or inspection. Ground wire  20  is attached to clamp  22  on housing  24  of fixture  14 . Conduit  28  contains conductors  18  and  20  and normally extends to an electrical service box in a location remote to fixture  14 . Conduit  28  is sealed to housing  24  by seal  29 . Plug  30 , disclosed herein, may be used to seal the entrance to conduit  28  to prevent water  10 , normally at a level above fixture  14 , entering conduit  28 . Plug  30  may seal with the inside surface of conduit  28  or with any extension, adapter attached to conduit  28 , or other connection with conduit  28 . It should be understood that sealing inside any such attachment to conduit  28 , such as an adapter or a housing of a niche, will be considered as sealing with the inside surface of conduit  28  and any such extension or attachment to a conduit where it is contiguous with a pool may be considered as a part of the conduit.  
         [0019]    Referring to FIG. 2, one embodiment of seal or plug  30  is shown. Opening  32  is provided for an insulated cable, such as cable  18  of FIG. 1, and opening  34  is provided for a second conductor, such as ground wire  20  of FIG. 1. Head  31  (FIG. 2) is adapted to assist in placement and removal of plug  30  from a conduit. Cylinder  36  of plug  30  is adaptably sized for sealing in an electrical conduit. Sealing surface  38  may be corrugated (as shown) to assist in sealing after insertion into a conduit. Corrugations may be rounded, as shown in one inset, or may have other profiles, such as the directional fins shown in the second inset of FIG. 2. Plug  30  may be installed on cable or wire such as shown in FIG. 1 by sliding the plug from the end of the cable or wire that will be attached to electrical service to a position very near (within about 1 foot) where cable  18  enters into a fixture such as light  16  (FIG. 1). Alternatively, seal  30  may be placed at a position about 3 to 5 feet from the entry of the cable into a fixture. This 3 to 5 feet allows loops  18 A to be formed in housing  34 . Alternatively, seal or plug  30  may be molded or otherwise sealed permanently onto cable  18  and ground wire  20  during manufacture of a fixture such as light  16 , such as shown in FIG. 2A. Plug  30  may be permanently affixed very near or at a selected distance from the entry of cable  18  into light  16 , so as to allow loops such as shown at  18 A to be formed in cable  18  within a housing. An installer of a fixture then may insert cables  18  and  20  into a conduit where it is contiguous with a pool and pulls cables  18  and  20  through a conduit until plug  30  can be inserted into the end of the conduit.  
         [0020]    Plug  30  may be formed from a deformable material, such as an elastomeric material, such as rubber. Alternatively, plug  30  may be formed of other polymeric material. A liquid that cures to an elastomeric material or a grease may be applied to plug  30  before or after deployment of the plug into a conduit.  
         [0021]    Referring to FIG. 3, plug  40  is a split plug similar to plug  30  of FIG. 1. Head  41  is adapted to insertion or removal of plug  40  into a conduit. Openings  42  and  44 , intersected by the split surface, are adapted to enclose electrical cable or wire such as described above. Half-cylinder  46  is adapted to mate with a matching half-cylinder in a conduit. Surface  48  may be corrugated in the shape shown in FIG. 3 or may have other shapes such as shown in the inset of FIG. 2. Plug  40  may be used to add a plug in a conduit to an existing pool without removing cable or wire from the conduit leading to the pool. This addition may be particularly important if a water leak is identified or suspected in the conduit.  
         [0022]    Referring to FIG. 4, plug  50  is shown, which contains head  51  and openings  52  and  54 . Cylinder  56  is adapted for use in a selected conduit size and may be formed from a deformable material such as rubber. Cylindrical surface  58  may be smooth and may be tapered to a smaller diameter at the end. Alternatively, plug  50  having cylinder  56  may be formed from a rigid material such as metal and surface  58  may contain one or more o-ring grooves  59 , which are adapted to receive o-rings for sealing inside a selected conduit. O-ring grooves may also be placed in openings  52  and  54  (not shown) for sealing around cables.  
         [0023]    Referring to FIG. 5, a split version of plug  50  (without o-ring grooves) is shown as matching half-cylinders  60 . Head  61  and half-cylinder openings  62  and  64 , intersected by the split, are adapted to enclose cables or wire. Half-cylinders  66  are adapted to seal inside a conduit. Surface  68  may be smooth. Plug  60  may be formed of a deformable material.  
         [0024]    Referring to FIG. 6, plug  30  in the end of conduit  28  is shown. Adapter  70  is preferably attached to the end of conduit  28  before housing  24  is installed (FIG. 1). It may be attached by an adhesive. Electrical conductors are passed through openings  32  and  34  before plug  30  is installed in conduit  28 .  
         [0025]    Referring to FIG. 7, housing  24  is attached to adapter  70 . In one embodiment, housing  24  is formed to include a male connector, such as threads, inside the niche formed by housing  24 . Plug  50 , which is shown as having a tapered cylindrical surface, is then inserted in the end of conduit  28  and cap  72 , which may be threadably attached to housing  24 , may be installed. Cap  72  may force plug  50  into housing  24  and adapter  70  and increase the sealing force between a tapered surface of plug  50  and the internal surface of housing  24  or adapter  70  and cables passing therethrough.  
         [0026]    [0026]FIG. 8 is a composite drawing such as in FIG. 1, showing plug  50  in place of plug  30 . It should be understood that any of the plugs described herein may be used as shown in FIG. 1 and FIG. 8.  
         [0027]    While the invention has been described with respect to some preferred embodiments, it should be understood that the invention is limited only by the scope of the claims below.