NOV. 12, 1946. G_ B, BENANDER 2,411,017 OUTLET BOX AND GROUND STRAP PROVIDED WITH CABLE CLAMPS Original Filed April 11, 1942 Inventor‘: GGQiQ B. ehander; H635 Attornetg. Patented Nov. 12, 1946 _ ' 2,411,017 UNITED \ ‘STATE s; PATENT ‘OFFICE f I ' 2,411,017 OUTLET BOX AND GROUND STRAP BRO VIDED WITH CABLE CLAMPS . George B. Benandelgloakla‘wn, R.‘ I., assignor to Monowatt Electrical Corporation, a. corporation of Connecticut , Original application April 11, 1942, Serial No. 438,545. Divided and this application April 19, 1944, Serial No. 531,797 5 Claims. 1 This application is a division of my applica tion Serial No. 438,545, ?led April 11, 1942, issued as Patent No. 2,362,794, November 14, 1944. The present invention relates to wiring devices of the type in which the device is part of the box for enclosing the connections to the power con ductors. Such a wiring device is particularly adapted to surface wiring systems and may be . (Cl. 174-51) ' . , 2. conductors. ‘Ifhe openings are formed partly in the base and partly in the cover and are blocked by knockouts 6, 7, and 8 of different‘sizes, one or more of which are removed depending upon the size and type of power conductor to be ‘con nected to the device. Along the sides of the cover and base at each end are knockouts 8 for use in open wiring. The covers are attached to the re termed a combined outlet and outlet box.‘ spective bases by screws in threaded into sockets It is desirable .that the devices be capable of 10 II in the base, and when assembled the base use in wiring systems using metallic armored and cover serve as an outlet box for enclosingthe cable, non-metallic cable (cable having a non metallic sheath 0r armor) and knob and'tube open wiring. In the metallic armored cable device and its connections with the power con ductors clamped between the cover and base. . When the wiring devices are used with metallic system, a continuous ground connection must be 15 armored cable, the ground connection to the carried through the metallic armor. In the pres armor is made through a ground strap l2 having ent invention this is done by means of a ground. screw holes l3 inline with the screw holes 3 in strap used interchangeably with each of the de-_ the base so-that the ground strap and base are vices and having clampsfor holding the cable secured to the support by the same screws. The and making the ground connection to the metal~ 20 base is seated on the ground strap with its ends lic armor.' In systems using non-metallic cable con?ned between upwardly extending ?anges H or open wiring, the ground strap is not necessary .at the ends of the ground. strap. At the top the and its expense is eliminated.‘ The object of my invention is- to provide an ?anges M are bent outwardly to provide horizon tal ?anges I-5 which are suitably indented at improved construction and arrangement in wir 25 IE to provide the lower half of a clamp for grip, ing devices of this type, particularly an improved ping metallic armored cable. The upper half of grounding strap and for a consideration of what ' the clamp is provided by a clamping member I‘! I'believe to be novel and my invention, attention having tongues 88 slidable in slots IS in the is directed to the following description and the ?anges l5 and having tongues 20 extending along claims appended thereto. 30 the inner faces of the ?anges M. The'upper In the accompanying drawing, Fig. 1 is a top clamping member I‘! at its top is provided with a plan view of part of a surface wiring system tapered recess 2| of the same shape as the ta using metallic‘ armored power conductors and pered projection 22 at the ends of the base and wiring devices embodying my invention; Fig. 2 is , cover so the device may be assembled on the a view similar to Fig. 1 with the covers of the 35 ground strap without disassembling the clamp. wiring devices removed; Fig. 3 is an exploded ' perspective view or the switch appearing in Fig. 1; and Fig. 4 is an exploded perspective view of The tongues 20 which project inwardly beyond the extreme ends of the base and cover serve to locate the device on the ground strap. The clamping members are held together by screws Referring to the drawing, each of the wiring 40 23 extending loosely through the center of the devices has an elongated base I and a cover 2 upper clamping member I‘! and threaded into the both of which may be made of suitable molded ‘ center of the ?ange I5. The upper clamping insulating material. The baseis provided with member is indented at 24 and is provided with screw holes 3 for attachment to a supporting a ?ange 24a for more effectively gripping metal surface and is narrow enough so that it can be 45 lic cable. As shown more clearly in Fig. 2, the attached to the narrow edge of two-by-four openings through the clamps are in line with the _ framingv when used in an open wiring system. openings in the device. ‘ Along the sides of the base members are projec~ In the single pole switch, as shown most clearly tions 4 which are of different sizes and which ?t ‘in Fig. 3, the base is provided with a hollow in corresponding depressions 5 in the sidescf 60 projection 25 housing the switch mechanism the respective covers. The projections and de which need not be illustrated for the purposes of pressions 4 and 5 insure that the covers are as the present invention. Across the open top of the semblecl with and properly positioned on the hollow projection 25 are a strip of insulating ma bases for which’ they are designed. At each end terial 26 and a metal strap 21 ?xed by screws 28 the lamp socket appearing in Fig. 1. . of the device are two openings for armored power 55 to the ends of the projection 25. The strap 27 2,411,017 g is provided with a slot v28' through which the switch handle 28 of molded insulating material projects and is provided with arcuate seats St on each side of the slot 28' pivotally engaged . the device and its enclosing box comprise a co - plete unit with the openings and clamps for power conductors.‘ The terminals for the device are located on opposite sides of the enclosing box, - by projections 88 integral with the switch han die. ‘The switch handle accordingly is pivoted on the strap 2?. At opposite ends the strap 2? is provided with terminal screws 82 so that the strap, which is insulated from‘ the switch, may be used as a bus bar. At one side of the base is 10 and at the center is a bus bar insulated from the device which, as described above, may be used .to feed a circuit through the device without the use of jumpers or other connections. The wiringis accordingly simpli?ed since all of the wiring con nections are made to terminal screws. . ?xed a conductive strip or bus bards having ter The use of the devices is further simpli?ed by minal screws 35 at opposite ends and at one end ‘the conductor clamping arrangement having . having an integral arm 35 (Fig. 2) connected to knockouts 8, l, and 8 for use with #12 and #1t two and three conductor metallic and non 25. The other switch contact is connected to a 15 ,metallic armored cable and knockouts @- for use strip 85 carrying a terminal screw 37 which is on p with #12 and #14 open wiring. The knockouts the opposite side of the base; from the terminals ‘ 8, ‘i, and 8 are spaced apart along conductor re 3t. ' The switch terminals 85 and 31 are accord ceiving grooves St at each-end of the base i and ingly on opposite sides of the base, and the cover 2. The knockouts 8 are at the outer ends mounting strap or bus bar 21 which is insulated 20 of the grooves and have surfaces 85 for gripping from the switch terminals and is used to elimi two conductor non-metallic "cable in sizes #12 nate the need for a jumper extends lengthwisev and, #14. The knockouts ‘I are arranged in of the base at the center. The switch handle channels 88 transvetl se to the length of the grooves one of the switch contacts inside the projection 29 projects out through a slot 88 in the cover. 85 and have surfs ees 81 projecting above the \ When the switch is used to control a device at 25 grooves st'pfor gripping three conductor non~ the end of a power ‘line, as shown in Figs. 1 and 2, metallic and metallic armored cable in size #14 the ground conductors 39 and 48 are connected and two conductor metallic armored cable in sizes by the terminal screws 82 to opposite'ends of the #12 and #14. The knockouts ‘i may be removed strap 27; The incoming live conductor 4! is con by a screw driver or similar prying tool inserted _ nected to the terminal screw 34 at one end of 30 into the space between the knockout and the the switch, and the outgoing live conductor s2 sides of the channel 88. The knockouts 8 have is connected to the terminal screw 3i at the oppo thin removable sections 88 at the inner edges of site end. The circuit between the terminal screws ribs 89. The sections 88 form closures for the 34 and 81 is respectively made and broken in the’ von and oil‘ positions of the switch. ' - _ grooves 84 and when removed provide su?icient 35 space for leading the conductors into the device In the lamp socket, as shown more clearly in as illustrated in Fig. 2. The grooves 84 are shaped Fig. 4, the base I is provided at the center with to properly grip ‘the largest cable (three con a cylindrical projection 43 on the upper-end of ductor #12 non-metallic and metallic. armored which is mounted a screw shell 44, and the cover 2 cable) for which the devices arev designed. By_ is provided with a cylindrical projection 45 sur 40 removing one or more of the knockouts 6, ‘I, and 8, rounding the upper end of the screw shell- The the device may be used with the customary sizes screw shell is ?xed on the upper end of the projec of armored cable. No adjustment of the con tion 43 by screws 48 threaded into the projection ductor clamp is' required other than the selective through a ?ange 41‘ at the bottom of the screw . removal of the proper knockouts. shell. Integral with the screw shell ‘is a metal 45 strip 48 connected to a terminal strip 49 by means Because-oi’ the correlation of the wiring devices and the ground strap,‘ the expense of wiring is of a screw 58 threaded through the strips 48 and ' ‘decreased since the same wiring devices are inter .49 intothe base. The strip 48 at'opposite ends is provided with terminal screws-5|. Within the ' ' changeably usable with non-metallic and metallic armored cable and the groundstrap need be sup screw shell is a center contact-52 ?xed to the 50 plied only ior metallic armored cable. ' _ _ upper. end'of the projection 43 by a rivet 53 which What I claim as new and desire to secure by connects ,the center contact to one end of strip ' Letters Patent of the United‘ States is: - 54 on the under side of the projection 43. The 1. A metallic ground strap ior'use with a wir other end of the strip 54 is connected by a rivet ing ‘device, said device comprising a housing of 55 to a terminal strip 56 provided at opposite 55 insulating .material enclosing connector‘ mem ends with terminal screws 51. The socket bers, said housing comprising a base’ having a terminal screws 5| and 51, like the switch terminal ?at bottom adapted to rest on a supporting sur screws 34 and 31, areat opposite sides of the‘ base. ‘ lace and a cover,- and having cable admission At the center of the base is a terminal strip or bus. openings and associated clamps for non-‘metallic bar 58, provided at opposite ends with terminal 60 armored cable, said ground strap comprising a screws 59 and extending up over the top of the ?at strip of metal having upturned ?anges inte projection 43 through a ‘groove 80. The bus bar grally formed therewith at the ‘ends ‘of, said strip, 58 extends beneath the screw shell 44 and center said ?anges being spaced to receive between contact 52 and is insulated therefrom‘by a strip them said housing, said ?anges having inwardly of insulating material 6| in the groove 60 on top 65 curved top surfaces on which the metallic armor of the bus bar 58. The bus bar 58 eliminates the of a metallic armored cable may lie, top clamp need for jumpers in the same manner as the bus members having downwardly facing surfaces complementary to said ?rst named surfaces, and struction. In the wiring system shown in Figs. 7 screws for positioning the top clamp members ' 1 and 2, the ground conductor‘ 40 is connected to 70 with respect to said ?anges, the spaces ‘between one of the terminal screws 5|, and the live con said ?anges and clamp members being so posi ductor 42 in series with the switch terminals 34 tioned that they are adapted to stand in line bar TL in the previously described switch con and 81 is connected to one of the terminal screws 51. ’ In each of the above described wiring devices‘ 75 ‘with the cable admission openings of said wirin,g e ce. / ' 2. In a surface wiring device, a ?at ground v 2,411,017 strap for attachment to a supporting surface, ' ?anges on said strap, a combined outlet and out let box of insulating material between said ?anges, clamps for metallic armored cable co operating with said ?anges, said clamps having portions against which the end walls of the box iii; to locate'the box_ between the ?anges, and ' cable admission openings in the box in line with said clamps‘. , V a 3. A metallic ground strap for use with a wir ing device, said device comprising a housing of insulating material enclosing connector mem- bers, said housing comprising a base having a , ?at bottom adapted to rest on a supporting sur face and a cover, and having cable admission openings, said ground strap comprising a ?at 4. The combination with a wiring device com prising a casing of insulating material having cable receiving openings in its end ‘walls and a ?at bottom wall, of a metallic ground strap com prising a ?at plate having at its two- ends ad justable cable clamps which position between them said casing with the clamps in line with said cable receiving openings, said ?at plate ?t ting against the ?at bottom wall of the casing 10 whereby when the wiring device is mounted on a wall the ?at plate lies between the ‘bottom of the casing and such wall, ' 5. The combination with a wiring device com prising a casing of insulating material having cable receiving openings in its end walls and a ?at bottom wall, of a metallic ground strap com prising a ?at plate having at its two ends ad strip of metal having upwardly projecting justable cable clamps which position between ?anges at its ends, said ?anges being spaced to them said casing with the clamps in line with receive between them said housing, said ?anges having upwardly facing top surfaces on which 20 said cable receiving openings, said-?at plate ?t ting against the ?at bottom wall of the casing wherebywhen the wiring device, is mounted on a wall the ?at plate lies between the bottom of the casing and such wall, and means providing to said ?rst named surfaces, and means for po sitioning the top clamping members with re 25 interengaging parts between the endwalls of the casing and the cable clamps to hold the cas spect to said ?anges, the spaces between said ing on the ground strap. ?anges and clamping members being so posi tioned that they are adapted, to stand in line GEORGE B. BENAl't'DER. ‘ with the cable admission openings of said wiring the metallic armor of a metallic armored cable may lie, top clamping members having down wardly facing clamping surfaces complementary device. '