US1902790A - Panel-board and panel-board construction - Google Patents

Description

March 21, 1933. F, TT 1,902,790

PANEL BOARD AND PANEL BOARD CONSTRUCTION Filed March 25, 1929 5 Sheets-Sheet l March 21, 1933. F STARRETT' 1,902,790

PANEL BOARD AND PANEL BOARD CONSTRUCTION Filed March 25, 1929 5 Sheets-Sheet 2 gmllmu Z4 I M, M ,U H m 1 12 26 i LZZJWZZV {gr I March 21, 1933. H, R T 1,902,790

PANEL BOARD AND PANEL BOARD CONSTRUCTION Filed March 25, 1929 5 Sheets-Sheet 5 A. v x

M nzzyeflwi March 21, 1933.

H. F. STARRETT PANEL BOARD AND PANEL BOARD CONSTRUCTION 5 SheetsSheet 4 Filed March 25, 1929 [My/mg March 21, 1933.

F. STARRETT PANEL BOARD AND PANEL BOARD CONSTRUCTION Filed March 25, 1929 5 Sheets-Sheet 5 Patented Mar. 21, 1933 PATENT OFFICE BIND-Y .l'. STABBETT, OI CHICAGO, ILLINOIS PAIR-BOARD 1ND PANEL-BOARD OONSTBUGIION Application filed Iarch 25, 1929. Serial No. 849,822.

This invention relates to improvements in panel-boards and panel-board construction, and more particularly to that type of panelboard which is equipped with a dead front;

that is, a panel-board of the type in which all the current and potential-carrying conductors are enclosed so as to prevent accidental contact therewith and consequent electrical shock.

More articularly, this invention relates to a panel-board of this type which is equipped with switches of the circuitbreaking type; that is, switches with which fuse protection is not necessary, the switch construction per se being such that it will open the circuit when it is exposed to overload currents.

One of the objects of this invention consists in the production of an improved and simplified construction whereby a very efiicient panel-board is obtained and in which construction the mounting space necessary for the switches, bus-bars and other currentcarrying conductors is minimized, so as to obtain a very compact as well as efiicient structure.

Another object of the invention resides in using the mounting for the switches together with the mounting plate for the switch mounting base and bus-bars so as to provide housings which are completely insulated for the panel-board feed bus-bars.

Another object of the invention resides in a special construction of the switch mounting base whereby it will provide the necessary air gap and potential creeping surfaces between the current-carrying conductors and metallic parts of the structure with a minimum amount of mounting base width and whereby the switch mounting bases are so de signed that the said bases can be readily removed from the panel-board mounting plate without removing the panel-board trim, and whereby the switch mounting bases together with the covers for the switch serve the dual purpose of a switch mounting and a barrier constituting one wall of the wiring gutter.

Other objects and features of this invention will become apparent from the following description and appended claims.

For the urpose of disclosin this invention one em ent thereof is illustrated in the accompanying drawings, in which:

Figure 1 is a front elevation of a cabinet and panel-board embodying this invention, parts being broken away to disclose more ally the interior construction;

Fig. 2 is a front elevation of the panelboard with the panel-board trim and door removed;

Fig. 3 is a front elevation of the panelboard proper with parts broken away, illustrating the manner of mounting the switches. and bus-bars on the panel-board mounting base, etc.

Fig. 4 is a cross-section taken on'the plane indicated by the line 4-4 of Fig. 3 looking in the direction of the arrows;

Fi 5 is a longitudinal cross-section of the pane -boa rd proper taken on the lane indicated by the line 5-5 of Fig. 3 looking in the direction of the arrows;

Fig. 6 is an illustration in rspective of the switch mounting base unit showing in detail the top construction of said base;

Fig. 7 is an illustration in pers tive of the switch mounting'base illustrating in detail the bottom construction of said base;

Fig. 8 is a front elevation of a panel-board unit with parts thereof broken away and fitted with an additional unit for providin fuse connections to the current-carrying and supplying bus-bars; and,

1g. 9 is a front elevation of the panelboard proper rovided with an additional unit to supply ses and a switch for the current-carrying and supplying bus-bars.

The construction illustrated comprises a cabinet or panel-board box 10 constructed of sheet steel, or other similar material, equipped with four sides and the bottom 11. This bottom 11 is equipped with four mounting screws such as 12 having the head on the under side of the bottom 11 and the screw threaded end thereof extending upwardl toward the panel-board proper. Loosely tted on each of these screws over the bottom 11 are the washers 13, over which are secured the adjustable threaded mounting discs 14. These discs 14 provide means for mounting the pahel-board mounting plate 15 in parallellsm with the wall in which the panelboard cabinet is to be positioned. Frequently these walls are not exactly true and the angle of the wall can be obtained for the mounting plate 15 by positioning the mounting discs 14 on their respective screws 12 in such position that the plate when solidly secured on these mounting discs by nuts such as 16 will lie in the same plane as the wall in which the anel-board is mounted.

The mounting plate 15 is preferably made of steel, although any other suitable material may be used. This steel plate carries the busbars and the branch switch mounting bases and can be removed and placed in the cabinet board box as a unit with all the circuit-controlling apparatus mounted thereon, as clearthe movab with the stationary contact 23; the movable 1y illustrated in Figs. 3 and 4.

The branch switch mounting bases such as 17 are secured to the sheet steel mounting plate 15 by screws such as 18 and 19. These screws 18 and 19 are so located as to be readily accessible from the front of the board so that a branch circuit switch with its mounting base can be readily removed with-. out disturbing any of the remainder of the apparatus on the panel-board, the screws being accessible by merely removing the branch circuit switch cover, such as 20, and an intermediate cover, such as 21, positioned between the covers of the branclt circuit switches aligned on either side of the mountin base 15.

he circuit-breaking switchsecured to the switch mounting base 17 can be any type of commercial circuit-breaking switch and does not constitute an part of this invention. The specific switc illustrated in the drawings, and particularly in Fig. 3, comprises e switch contact 22 cooperating contact bein actuated by the switch lever 24. The switch is provided with a coil 25 which, together with a thermostatic element, serves to actuate an armature to automaticall open the switch when a current overloa is flowing through the circuit. A further description of the switch is unnecessary as the switch does not constitute any part of this invention.

This switch is mounted upon the base 17, illustrated in detail in Figs. 6' and 7. As shown in these figures the base is provided with the mounting holes 26 and 27 which receive the mounting screws 19 and 18, respectively, for securing the switch to the mounting plate 15. The .base is provided with a cut-out portion 28 which serves as a channel through which bus- bars 29 or 30 are carried.

The mounting base is equipped on its top face over the cut-out portion 28 with a perforation 31. In this perforation is secured the depressed part of a current-carrying bar 32 with its lower face flush with the top face of the cut-out portion or channel 28.. That ortion of the current-carrying bar 32 whic is positioned in the perforation 31 is fitted with a hole 33 which receives a screw 34 for securing a bus-bar, such as either 29 or 30, to the current-carrying bar 32.

The movable contact 23 of the switch connects the bar 32 to the current-carrying bar 34 through which the current from the busbar is carried to the branch line terminal 35, by way of the current-carrying bar 36. The branch line terminal 35 is positioned in a cut-out portion 37 in the mountin base 17.

As illustrated in Figures 6 and the cutout portion 28 which serves to form the busbar channel does not extend to the bottom face of the branch switch mounting base 17 but terminates short of this base, sothat another channel 38 is formed in the branch switch mounting base.

This channel 38 is provided to form a housing for an" insulating plate 39 (Fig. 3) which is held in position on the steel mounting plate 15 by the side walls 40 and 41 of the channel 38, the insulating base 42 at the top of thepanel-board and the insulating base 43 at the bottom of the panel-board. It will consequently be apparent that the side walls 40 and 41 of the channel 38 of the several switch mounting bases, together with the insulating in conjunction with said plate 39 serve to form an insulated housing for either the busbars 29 or 30. This housing for the bus-bars 29'is clearly illustrated in Figs. 4 and 5.

Referring to Figs. 2, 3 and 6, it will be observed that the conducting bar which connects with the branch line terminal 35 is given an angle of inclination toward the center of the mounting base. This angle of inclination toward the center of the base is provided so as to incorporate in the construction the necessary surface bemetallic parts of the construction, so, as to prevent creeping of potential, also to incorporate the necessary air distance between conducting parts so asto provide the necessary air insulation.

The base 17 on its lower surface is liketween the conducting bar and the other wise equipped with the cut-out portion 50 which is provided so that the necessary creeplng surface will be incorporated in this construction between the branch line terminal and the mounting base 15. By providing mounting base 17 can be minimized and the required creeping surfaces as well as the necessary air insulation between metallic parts can be maintained. 7

As illustrated in Figs. 1, 2 and 3, these mounting bases 17 are mounted side-by-side on either side of the metal mounting plate 15. When thus mounted the cut-out portions 28 in each mounting base, as hereinbefore described, provide the channel for the bus- bars 29 or 30. The'bus-bars when positioned in this channel can be directly connected to the conducting bar 32, since this bar is fitted into the perforation 31 so'that it will directly contact with the bus- bars 29 or 30, to either one of which it maybe directly connected b a screw such as 34. This interconnection etween the conducting bar 32 and the bus-bar serves to osition the bus-bar in place in its insulate housing or channel, and likewise serves to make a solid contact between the conducting bar 32 of the switch and one of the bus-bars, either 29 or 30.

As illustrated in Figs. 3 and 4, it is sometimes essential to stiffen the mounting plate 15. This becomes necessary when a large number of'branch line switches are to be mounted on this plate. Fig. 3 illustrates a anel-board which is broken at51 and it will obvious that intermediate this break any number of, branch line switches may be mounted. When a large number of such switches are mounted on the base it may be stifi'ened by means of a metal strip 52 which extends over that portion of the length of the mounting plate 15 on which the branch line switches are mounted.' Thestrip 52 is secured to the mounting plate 15 by means of screws such as 53; the strip being mounted on washers such as 54.

Secured to this strip 52 are a plurality of -metallic bars such as 55 which extend upwardly and are provided at their upper ends with the turnover portion 56 which serves to receive a cover-plate 21, which is mounted on the part 56 by means of screws such as 58.

When the strip 52 is not used the bars 55 are" secured directly to the plate 15.

This cover plate 21, together with the cover 59 for each of the switches, serves to make the panel-board a dead front board for that. part of the apparatus which contains the branch line switches and the busbar connections to said switches.

Mounted at the top of the steel mounting plate 15 is the insulating base 42 which carrie's the line terminals 60 constituting the branch line connection for. the other side of each branch line circuit. These branch line terminals 60 are secured on a bus-bar 61 to which is connected the other terminal of the main line circuit by means of the lug 62 which in turn is connected to the lead from the other side of the line.

The base 42 carrying the bus bar 61 and the line terminal 60 is enclosed in the insulated cover 63. This cover is held in position by means of screws 64 which are threaded into the upper portion of bars 65 in turn secured to the base 42 inany convenient manner. (See Fig. 5.)

The bus- bars 29 and 30 are connected to terminal lugs 68 and 69 by any suitable means, as, for example, the nuts 1y. These ends of the bus- bars 29 and 30 together with the terminals 68 and 69 are mounted on the insulating bwe 43, and this base together with the ends of the bus-bars and the terminals are enclosed in the housing 74. The housing 74 is secured in position by the screws 75 which are threaded into the upper part of the uprights 76, the lower ends of O and 71, respectivewhich are secured to the. insulated base 43 in any suitable manner.

Itwill be evident Zrom this description that I to position an insulating strip on the base 15, a an together with said strip serve to enclose the bus-bars feeding the branch line switches in an insulated housing. The mounting plate 15 is likewise equipped. with the insulating base 43 which carries the terminals for the bus-bars and the insulating base 42 which carries the bus-bar for the second terminal of the branch line circuits. Each of the branch line switches is provided with an insulating cover such as 20, the base 42 with an insulating cover 63, and the base 43 with an insulating cover 74. The covers 63, 74 and the switch covers 20 and 21 serve to completely enclose all the current-carrying conductors on the panel-board and unite to make the panel-board a dead front panelboard. Moreover, any one of these switch covers 20 and cover 21 or the covers 63 and 74 for the terminal mountings 42 and 43 respectively, can be removed independently of the rest of the equipment so as to give access to the equipment thereunder if necessary.

It will also be evident that the peripheral edge of the cover plates 20 for the switches together with the cover plates 63 and 74 for the bases 42 and 43, respectively, constitute for the switches and mounting bases 42 and 43, respectively, and the outer wall of the cabinet or panel-board box 10.

From the above description it will be apparent that the branch switch mounting base is so constructed as to serve a plurality of purposes and that the cover lates or housings for the branch switches, or the mounting base for the bus-bars 61 and the mounting base'for the terminals of the bus- bars 29 and 30 serve not onlyto enclose the current-carrying conductors of these devices but also unite to provide an insulating wall which constitutes a barrier-wall for a wiring gutter.

Moreover, it will be apparent that the mounting screws 18 and 19 for each of the branch line switch mounting bases are sojpositioned that when the cover 20 for said switch and the intermediate coverplate 21 are removed they are readily accessible and the base together with the branch line switch can then be removed from the panel-board by removing the mounting screws 18 and 19 and the screw 34 which secures the conductingv lug 32 to either bus- bar 29 or 30.

Vith this character of construction, therefore, in case of trouble with any part of the equipment on the panel-board, the part affected can be readily removed, repaired and replaced without in any way molesting the rest of the equipment of the panel board. This, obviously, makes a very flexible construction.

The intermediate cover 21, as illustrated in Figs. 1 and 2, is equipped with designation plates such as 80. These designation plates are made of any suitable material and are secured to the cover 21 by screws, rivets or in any other well known manner. 7 The plates are equipped on either side with a'turnedover edge so that they will readily receive and hold the ordinary card or strip on which the circuit designation is displayed. One end of each of these designation plates 80 is formed in the shape of an arrow such as 81, the purpose of which arrow is to point to the particular branch circuit with which the designation is associated. The designation plates are so located on the cover 21 so that one points to the switch on the left side of the panel-board and the next one tothe switch on the right side of the panel-board. Each branch switch cover 20 has placed thereon the designations On and OK to indicate the condition of the switch mechanism to the operator actuating the operating lever of the switch 24 when the cover is in position. With these designations placed on the covers 20 and 21-. the condition of all the circuits in the panel-boards will be readily apparent to the observer from an inspection of the front of the board.

the bus-bar 61 and its associated connections, this can be readily obtained without molesting any of the panel-board connections or apparatus by merely: removing the screw 64 and the cover 63. ikewise, 1f access is desired to the bus- bar line terminals 68 and 69,

this can be obtained merely by removingrthe screw and the insulating cover 74.- his does not in any way molest the rest of th f .I a. 5 esired to equip a panel-board,

panel-board equipment. I

When it is such as illustrated in Figs. 1 to 5, with fuses for the bus-bars, the terminal 43, its cover plate 74 and associated equipment is not used and in place thereof the unit 84 is utilized. e

(See Fig. 8) This unit comprises a base 85 on which are mounted the fuse clips 86, 87, 88

and 89. The fuse clips 86 and 88 are'connected to the bus- bars 29 and 30 by an suitable means such as the nuts 90 and 91 whereas the line connections are electrically connected to the fuse clips 87 and 89 by suitable means such as the nuts 92 and 93 which'are positioned on the lateral projections 94 and 95 of the clips 87 and 89, respectively.

When a fuse connection for the bus-bars 29 and 30' is desired with a panel-board construction such as illustrated in Figure 8, it preferably fitted with a cover 96 which is equipped with a door 97 whichcan be readily opened to give access to the fuses 98 and 99 secured between the .fuse terminals.

The only difference in the construction illustrated in Figure 8 from that shown in.

Figs. 1 to 5, inclusive, is that the bus-bar terminal 43 and its associated equipment and cover 74 of Figs. 1 to 5 is replaced y the base 84 and its associated equipment and cover.

Likewise, if it is desired to use with the panel-board a fused bus-bar connection as well as a panel-board switch for controlling the flow of current through the bus-bars, then' the unit 84 and associated equipment of Fig. 8 is replaced by the unit 100 and associated equipment of Fig. 9. This unit 100 contains fuse clips 101, 102, 103 and 104 which are secured to a terminal 105 in the same manner as this same apparatus is connected to the terminal 85 of Figure 8.

Connected to the fuse clips 102 and 104 are the conducting bars 106 and 107 which in turn are electrically connected to the conducting bars 108 and 109 with which two of the movable contacts 110 and 111 of any suitable switch connect. The other ends of the movable terminals 110 and 111 of the switch connect with the contact bars 112 and 113 which, in turn, are connected by means of the nuts 114 and 115 with the line terminals.

The fuse connections as well as the switch '116 and its associated contacts are mounted on a suitable insulating terminal and are protected by a cover plate 117. Secured to this cover plate by. hinges 118 and 119 is a cover 120 which may be raised to give access to the fuses 121 and 122 interconnecting the fuse clip terminals 103 and 104 and 101 and 102, respectively.

Any suitable t of switch and fuse connection can read 17; be used with the panelboard positioned a ove the unit base 100 and if-desired the switch operating mechanism can be so inter-related with the hinged door 120 of the fuse chamber that an interlocking will result whereby the door 120 cannot be opened when the switch is in its closed posit1on and the switch cannot be closed when the door 120 'is in its open positiom Any one of the well known commercial mechanisms for accomplishing this result may be utilized and the particular character of switch and fuse connection per so used with the anel-board does not constitute any part of t invention.

The conducting bars 112 and 113 together with the nuts 114 and 115 associated therewith for connecting the line connections to the outside terminals of the switch 116 are protected by an insulating covering 125 which is secured to the base in any suitable manner, preferably in the manner illustrated in Fig. 5 for the insulating cover 74. When this method of connection is utilized this cover can be put into position or removed through the agency of the screws 126 and 127 so as to expose the conducting bars 114 and 115.

A se arate cover plate 125 is provided at the end of the unit 100 so that the line terminals 114 and 115 will be readily accessible to make the line connections by merely removing the cover plate 125 and not molesting any of the rest of the equipment on the board. If this separate cover plate 125 were not provided it would be necessary to remove the plate covering the fuses 121 and 122, as well as the switch (116) connections, and this would be necessary every time, itbecame desirable to inspect the line connections.

By using the separate cover plate 125 the fuse and switch connections do not have to be exposed and the conducting bars 113 and 112 with the associated nuts 114 and 115 for receiving the line wires are easily and rapidly exposed for inspection or for other purposes by merely removing the cover 125.

' From the foregoing description it will be apparent that the improved panel-board construction herein described com uses a very flexible unit in which any of t e apparatus mounted on the board is readily accessible by merely removing a small cover plate wh ch exposes only that part of the apparatus which it is desired to remove or inspect; that the panel-board proper, as illustrated in Flgs. 1 to 7, is designed and constructed so as to minimize mounting centers and utilize ciliciently all the insulating materials incorporated in the construction, which rovides the necessary insulating covers for us-bars and switch connections, and the proper spac ings between current-carrying conductors and metallic parts, so that the essential air gaps and potential creeping surfaces will be maintaine throughout the equipment.

Moreover, by using the equi ment illustrated in Figs. 1 to 5, and mere y replacing the terminal 43 and its associated equipment by either a unit such as illustrated at 84 on Fig. 8, or at 100 on Fig. 9, the panel-board 'materially reduce the ultimate dimensions of the panel-board because of the reduction of mounting centers between the respective branch line circuits. 1

Obviously the invention is not limited to the preferred form thereof which is herein illustrated and described butis capable of many variations and modifications without departing from the spirit and scope of the invention as set forth in the following claims.

What is claimed is:

1. A panel-board comprising, in combination, a panel-box enclosure, a metallic panelboard mounting plate positioned in said box, insulated branch switch mounting bases secured thereto, a strip of insulatin material positioned on said plate, a steppe longitumal channel formed by the assembled switch mounting bases, the wider stepped channel serving to laterally position said insulating strip, and a panel-board bus-bar, said bus-bar being channe 2. A panel-board comprising, in combination, a panel-box enclosure, a metallic panelboard mounting plate positioned in said box, insulating branch switch mounting bases secured thereto, a strip of insulating material positioned on said plate, a stepped longitudinal channel formed by the assembled switch mounting bases, a panel-board bus-bar, the narrower stepped channel and said insulating bases serving as an insulated channel to enclose said bus-bar.

positioned in the narrower stepped 3. A panel-board comprising, in combina- I tion, apanel-box enclosure, a metallic panelboard mounting plate positioned in said box, insulating branch switch mounting'bases secured thereto, a stri of insulating material positioned on said ate, a stepped longitudinal channel formed by the assembled switch 'rnounting bases, the wider stepped channel of said plate, branch line switches secured bases, an insulating cover line switch, supporting to said mountin for each "branc means extendin upwardly from said plate nation, a panel-box enclosure,

and an insulating cover 'tioned 'inter mediate 'said longitudina 'rows of: line switches and mounted on said supporting means." v j 5. A panel-board comprising, in combi insulated branch switch mounting bases secured in two longitudinal rows in said enclosure, branch.

line switches secured to said mounting bases, an insulating cover for each branch lme switch, an insulating cover positioned mtermediate said longitudinal -rows of line switches, and mounting screws for securing said bases in said enclosures accessible from the front of the board, one of said screws being positioned under the line switch cover,

and the other of the screws being positioned under the intermediate cover. 7

6. A panel-board comprising, in combination, a panel-box enclosure, a metallic panelboard mounting plate positioned in said box, insulating branch switch mounting bases secured thereto, a metal reinforcin stri secured to and extending along the; ace 0 said mounting plate, mounting means positioned on said strip and an insulating cover'plate secured to said means for enclosing the area between said mounting bases. 4

7. A panel-board comprising, in combination, a panel-boxfenclosure, a metall1c panelboard mounting plate positioned n said box, insulating branch switch mounting bases secured thereto, a metal reinforcing strip secured to and extending along the face of said mounting plate, current-carrying conductors secured to'said bases, mount means ositioned on said reinforcing strip, insulatmg housings for said mounting bases, and an insulating cover plate secured to sa1d means, said housings and said cover plate forming a dead front for the area of said board in which the said bases are situated.

8. A panel-board comprising, in combination, a panel-box enclosure, a metallic panelboard mounting plate positioned in said box, insulating branch switch mounting bases se-' cured thereto, insulating housings for said switch mounting bases, an insulating termi-. nal base, a line terminal bus-bar mounted thereon, a second insulating terminal base,

panel-boardbus-bars, terminals for said busswitch for a bars mounted on said second base, and in dividual insulating housings for each of said bases. v

9. A panel-board comprising, in combination, a panel-box enclosure, a metallic anelboard mounting plate positioned in sai box,

insulating branch switch'mounting bases secured thereto, insulating housings for each of said switch mounting bases, two insulating bases, each adapted to" carry bus-bar termmal equipment, insulating housings for each of said branch switch mounting bases and said terminal bases, a wiring gutter sur rounding said mounting late, the said insulating housings for said terminal --mounting bases and said branch-switch mounting bases combining to form one continuous wall for sa1d wiring gutter.

i 10. A panel-board comprising, in combination, a anel-box enclosure, a panelboard mounting plate positioned in said box, insulating branch line switch mounting bases secured thereto, an insulatin bus-bar terminal base positioned at eac end of said mounting plate, a wiring gutter surrounding said mounting late, and separate individual .jinsulating ousings for each of saidbases, the said insulating housings for all of said bases combining to form one continuous wall for said wiring gutter. v

11. A mounting for a current-controlling panel-board comprising an insulating base aving a stepped channel in its lower. face, an insulatin plate positioned in the lower step of sai stepped channel, said plate, togetherwith the upper channel, serving to form an insulated housin for current-carrying conductors feeding the board. Y

' 12. A mounting base for a current-controlling switch for a panel-board, comprisin an insulating base, a branch line termini, a depression in said base in which said branch line terminal is positioned, a terminal member connected to said branch line terminal, said terminal member being out of contact with said base for a portion of its length for the purpose of increasing the potential creeping surface between said terminal and other metallic parts -on which the base may be mounted.

13. A mounting base for a current-controlling switch for a panel-board, comprising an insulating base, a branch line terminal, a depression of said base in which said branch line terminal is positioned, a terminal member connected to said branch line terminal, said terminal member being shaped so as to be out of contact with said base for a portion of its length, a cut-out portion located on the bottom of said base opposite the said depression whereby the length of the'po'tential creeping surface from the terminal to the metallic parts on which the'base may be mounted is increased.

panel- 'iis ' panel-board bus-bar,

i said plate, .a longitudinal 14. A panel-board comprising, in combination, a panel-box enclosure, a metallic panel-board mounting plate positioned in said box, insulating ranch switch mounting bases secured thereto, a strip of insulating material positioned on said plate and held in place by said bases, a anel-board bus-bar and means associated wit said bases for 'securingsaid bus-bar in said insulatin strip. 7

15. A pane -board comprising, in combination, a panel-box enclosure, a metallic panel-board mounting plate positioned in said box, insulating branch switch mounting bases secured thereto, a strip of insulating material, means in said bases for securing said strip on said plate under said bases, a and means associated with said bases for securing said bus-bar to said bases inposition above said insulating strip.

16. A panel-board comprising, in combination, a panel-box enclosure, a metallic panel-board mounting plate positioned in said box, insulating branch switch mounting bases secured thereto, current controllin apparatus secured to said mounting bases at ove channel formed by position above the assembled switch mounting bases above said plate, an insulating stri positioned on said plate in said channel, an d bus-bar ositioned in said channel above said insu ating strip. 1

In witness whereof, I have hereunto subscribed my name.

HENRY F. STARRETT.

a panel-board

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