CA1098610A - Bus bar construction and method - Google Patents
Bus bar construction and methodInfo
- Publication number
- CA1098610A CA1098610A CA306,187A CA306187A CA1098610A CA 1098610 A CA1098610 A CA 1098610A CA 306187 A CA306187 A CA 306187A CA 1098610 A CA1098610 A CA 1098610A
- Authority
- CA
- Canada
- Prior art keywords
- bus bar
- rivet
- shank
- plug
- aperture
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
- H01R4/00—Electrically-conductive connections between two or more conductive members in direct contact, i.e. touching one another; Means for effecting or maintaining such contact; Electrically-conductive connections having two or more spaced connecting locations for conductors and using contact members penetrating insulation
- H01R4/58—Electrically-conductive connections between two or more conductive members in direct contact, i.e. touching one another; Means for effecting or maintaining such contact; Electrically-conductive connections having two or more spaced connecting locations for conductors and using contact members penetrating insulation characterised by the form or material of the contacting members
- H01R4/62—Connections between conductors of different materials; Connections between or with aluminium or steel-core aluminium conductors
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H85/00—Protective devices in which the current flows through a part of fusible material and this current is interrupted by displacement of the fusible material when this current becomes excessive
- H01H85/02—Details
- H01H85/20—Bases for supporting the fuse; Separate parts thereof
- H01H85/2005—Bases for supporting the fuse; Separate parts thereof for use with screw-in type fuse
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
- H01R4/00—Electrically-conductive connections between two or more conductive members in direct contact, i.e. touching one another; Means for effecting or maintaining such contact; Electrically-conductive connections having two or more spaced connecting locations for conductors and using contact members penetrating insulation
- H01R4/06—Riveted connections
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02B—BOARDS, SUBSTATIONS OR SWITCHING ARRANGEMENTS FOR THE SUPPLY OR DISTRIBUTION OF ELECTRIC POWER
- H02B1/00—Frameworks, boards, panels, desks, casings; Details of substations or switching arrangements
- H02B1/20—Bus-bar or other wiring layouts, e.g. in cubicles, in switchyards
- H02B1/21—Bus-bar arrangements for rack-mounted devices with withdrawable units
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H85/00—Protective devices in which the current flows through a part of fusible material and this current is interrupted by displacement of the fusible material when this current becomes excessive
- H01H85/02—Details
- H01H85/20—Bases for supporting the fuse; Separate parts thereof
- H01H85/205—Electric connections to contacts on the base
- H01H2085/2055—Connections to bus bars in an installation with screw in type fuses or knife blade fuses
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Fuses (AREA)
Abstract
ABSTRACT
A bus bar construction for a fused residential panelboard using plug fuses is disclosed in which the contact point for each of the plug fuses is formed by a silver plated copper rivet driven into a punched aperture in the bus bar from the side of the bus bar remote from the side upon which the punching operation was conducted.
A bus bar construction for a fused residential panelboard using plug fuses is disclosed in which the contact point for each of the plug fuses is formed by a silver plated copper rivet driven into a punched aperture in the bus bar from the side of the bus bar remote from the side upon which the punching operation was conducted.
Description
~L~g~6~
The invention relates to fused residential panelboards oE
the kind using pluy fuses ancl, in particular, to a bus bar and plug fuse contact assembly for such panelboards.
A3 part of the wiring research program conducted by Ontario ~Iydro fused residential pa~elboards using pluy fuses were the sub-ject of investigation as a result of reports that such panelboards, have,on occasion, ~ailed in such a way as to create a ~ire hazard.
During the course of this investigation typical residential fused panelboards were purchased and tested at their rated capacities and measurements were made of the temperature rise at the contact point between plug fuse and bus bar interfaces.
Such tests were conducted under carefully controlled condi-tions simulating actual c~cling of such panelboards under load condi-tions when installed in normal service locations. Plug fuses were installed at predetermined torques so as to provide, from test to test, a relativ~ly constant fuse to bus bar pressure.
An analysis of the test results revealed that a number of failures were related to arcing at the fuse plug tips where contact is made with the bus bar and that such failures were most commonly 2Q associated with loads of a cyclic nature such as washing machines, water heaters, home heating units and other deYices which t under au~o-matic control, cycle between on and off conditions during their nor-mal operation.
~ s a result of ~hese conclusions~ Canadian Standards Association established new standards which must be met by fused residential panelboards in order to be entitled to Canadian Standards Association approval.
The criterion for these te3ts have been clearly set forth in electrical bulletin No. 1120 dated May 26, lg77 published by Canadian Standards Association and provide that such Eused domeqtic panel-boards, set up under the conditions set forth in the bulletin and cycled under simulated load for periods of one hour "on" and one-half hour "o~f" shall disclose no more than a 10C temperature r.ise between the fifth cycle and the two hundredth cycle and no more than a 15 C temperatuxe rise between the fiftieth cycle and the five hundredth cycle.
Panelboards of the kind commPrcially available prior to the present invention have consistently failed such a test and it is the object of the prasent invention to provide a bus bar, fuse contact assembly which, when subjected to the test designated by Canadian Standards Association will meet khese requirements and will enable a panelboard to achieve Canadian Standards Association approval.
Although other factors may have a hearing upon the ability of the pan21board to meet the Canadian Standards Association require-ments, it has been found that a significant factor resides in the fuse tip to bus bar contact and the principal object of the present invention is to provide an improved fuse tip to bus bar contact as will be described in detail with reference to the accompanying drawings in which like reference numerals denote like parts in the various views and in which:
Figure 1 is a plan view, with the cover partly cut away, of fused residential panelboard embodying the present:invsntion:
: Figure 2 is a Bection view taken along line 2-2 of Figure 1:
Figure 3 is an~exploded view, partly in section showiny a detail of the fuse t:ip contact and an associated portion of a bus ~bar: and : : :
Figure 4 is a section view taken along line 4-4 of Figure 1 showing, in addition, in dotted lines the fuse in position in contact : . - 3 -~:: ' ' :
36~C~
with the fuse contact point.
Referring now to Figure 1, th~ ~used c1omestic panelboard of a generally conventional kind is illustrated as being provided by an enclosure 10 which is formed of sheet metal and which is provided with known screw engaging deformationc; 11 by means of wllich a cover plate 12 may be secured in position by screws 13.
Within the enclosure 10 the bus bars 14 and 15 are mounted in spaced, parallel relationship, insulated from the enclosure 10 by means of stand-off insulators 16 which are secured to the enclosure 10 and to which the bus bars are secured in a conventional way.
Associated with the bus bars are cartridge fuse holders 17 of a conventional kind and plug fuse holders 18, also of a conven-tional kind all of which are provided with electrical terminals hy means of which the panelboard may be wired into the house or residen-tial circuitry.
~lectrical contact means 19 are provided by means of which electrical energy from the service ~ntrance line~ may be connected to the bus bars and ground connections are provided by a convenient bank of terminals c~uch as those illustrated by refPrence numeral ~0.
So far, everything that has been described is entirely con~
ventional and will be very familiar and well ~nown to those skilled in the art.
The essence of the invention is illustrated in Figures 3 and 4.
~ach bus bar 15 is provided, at spaced location~ along its length corresponding to the contact points for the plug fuses with silver plated copper rivets which are received in apertures formed in the bus bars.
Referring now to Figure 3, a bus bar 15 is shown in cross ~ section with the section line lying a~ong a diameter o~ an aperture :, ~
6~
22 adapted to r~ceive a rivet 21.
The aperture 22 is Eormed by a punchirlg operation with the punch being driven through the bus bar 15 in the directi.on of the arrow 23. Punching the bus har in thi.s manner provides an aperture 22 which, over a portion of its length, is provid~d with an essen-tially cylindrical wall 24 but, which is also provided~ over at least a portion of its length with a outwardly tapering wall portion 25.
This formation i5 common to the punchi.ng operation and is not, in itself, a novel phenomenon but it is important in the successful performance of the present inventionO
Each rivet 21 is provided with a cylindrical shank 26 w~ich is of a length at least as yreat and, preferably, slightly greater than the thickness T o~ the bus bar and of a diamet~r that is a force fit within at least that portion of the aperture 22 defined by the substantially cylindrical wall portion 24.
Each rivet 21 is provided with a disc-liXe head 27 of a dia-meter larger than the shank and, the free end of the shank is pro-vided with a ~onicaL re~ess ~a having a maximum diame~er slighkly less than the diameter of the shank for reasons which will be explained below.
13ach ris~et 21 is provided with a layer vf fine silver 28 that is deposited thereon and which is of ~he order of .`024 inches in ~thickness. After the layer of fine silver 28 has been deposited, the entire rivet, si:lver layer and all is further silver pla~ed.
The rivets 21 are then dri~en into the apertures 22 from the side of the bu~ bar :remote from the side from which the punching operation was performed. By inserting or driving the rivets from this side of the bùs bar, the seating of the rivets is somewhat ~acilitated in that the slightly ou~wardly flaring wall porticn 25 `
~ _ 5 _ .
'' ' provides the lead-in portion to enable the rivets to be properly seated. Furthermore, as t~e r.ivet i5 driven into th~ bus bar, some of the silver plating on the shank o~ the rivet illustrated at 29 in Figure 4 will be scraped off and will be forced into the small gap lying between ~he cylindrical shank of the rivet and the slightly outwardly flaring wall sur~ace 25 so clS to be compressed into intimate contact with both the coppar rivet ancl the copper bus bar at a loca-tion indicated by refer~nce character 30. Intimate electrical contact and heat exchange contact is, accordillgly, thereby provided between the entire shank of the rivet and the wall portion of the aperture 22 and the forceable driving of the rivet..into the bus bax also pro-vides for intimate electrical and heat exchange contact between the underside 31 of the rivet.head 27 as seen in Figure 4.
Optionally, once the rivet has been seated in the aperture in the bus bar as seen in Figure 4, it may be staked at two diametri-cally opposed points 32 and 33 as indica~ed by the arrows in Figure 4.
By this construction, a contact point is provided on the bus bar ~or each of the plug fuses shown in dotted lines at 34 in Figure 4 with the fuse tip contact 35 in intimate electrical and heat exchange contac~ with the silver plated face of the rivet head 270 ~ xtensive testing of a bus bar constructed in accordance wi~h the foregoing description in the environment of a fused domestic panelboard a~ illustrated in Figure l has enabled such a panelboard ~o meet the tempera-t;ure rise requirements of the Canadian Standards Association bulletin No. 1120 and, accordingly, provides a use~ul and sxgni~icant advance in the art.
- ' , ~.
The invention relates to fused residential panelboards oE
the kind using pluy fuses ancl, in particular, to a bus bar and plug fuse contact assembly for such panelboards.
A3 part of the wiring research program conducted by Ontario ~Iydro fused residential pa~elboards using pluy fuses were the sub-ject of investigation as a result of reports that such panelboards, have,on occasion, ~ailed in such a way as to create a ~ire hazard.
During the course of this investigation typical residential fused panelboards were purchased and tested at their rated capacities and measurements were made of the temperature rise at the contact point between plug fuse and bus bar interfaces.
Such tests were conducted under carefully controlled condi-tions simulating actual c~cling of such panelboards under load condi-tions when installed in normal service locations. Plug fuses were installed at predetermined torques so as to provide, from test to test, a relativ~ly constant fuse to bus bar pressure.
An analysis of the test results revealed that a number of failures were related to arcing at the fuse plug tips where contact is made with the bus bar and that such failures were most commonly 2Q associated with loads of a cyclic nature such as washing machines, water heaters, home heating units and other deYices which t under au~o-matic control, cycle between on and off conditions during their nor-mal operation.
~ s a result of ~hese conclusions~ Canadian Standards Association established new standards which must be met by fused residential panelboards in order to be entitled to Canadian Standards Association approval.
The criterion for these te3ts have been clearly set forth in electrical bulletin No. 1120 dated May 26, lg77 published by Canadian Standards Association and provide that such Eused domeqtic panel-boards, set up under the conditions set forth in the bulletin and cycled under simulated load for periods of one hour "on" and one-half hour "o~f" shall disclose no more than a 10C temperature r.ise between the fifth cycle and the two hundredth cycle and no more than a 15 C temperatuxe rise between the fiftieth cycle and the five hundredth cycle.
Panelboards of the kind commPrcially available prior to the present invention have consistently failed such a test and it is the object of the prasent invention to provide a bus bar, fuse contact assembly which, when subjected to the test designated by Canadian Standards Association will meet khese requirements and will enable a panelboard to achieve Canadian Standards Association approval.
Although other factors may have a hearing upon the ability of the pan21board to meet the Canadian Standards Association require-ments, it has been found that a significant factor resides in the fuse tip to bus bar contact and the principal object of the present invention is to provide an improved fuse tip to bus bar contact as will be described in detail with reference to the accompanying drawings in which like reference numerals denote like parts in the various views and in which:
Figure 1 is a plan view, with the cover partly cut away, of fused residential panelboard embodying the present:invsntion:
: Figure 2 is a Bection view taken along line 2-2 of Figure 1:
Figure 3 is an~exploded view, partly in section showiny a detail of the fuse t:ip contact and an associated portion of a bus ~bar: and : : :
Figure 4 is a section view taken along line 4-4 of Figure 1 showing, in addition, in dotted lines the fuse in position in contact : . - 3 -~:: ' ' :
36~C~
with the fuse contact point.
Referring now to Figure 1, th~ ~used c1omestic panelboard of a generally conventional kind is illustrated as being provided by an enclosure 10 which is formed of sheet metal and which is provided with known screw engaging deformationc; 11 by means of wllich a cover plate 12 may be secured in position by screws 13.
Within the enclosure 10 the bus bars 14 and 15 are mounted in spaced, parallel relationship, insulated from the enclosure 10 by means of stand-off insulators 16 which are secured to the enclosure 10 and to which the bus bars are secured in a conventional way.
Associated with the bus bars are cartridge fuse holders 17 of a conventional kind and plug fuse holders 18, also of a conven-tional kind all of which are provided with electrical terminals hy means of which the panelboard may be wired into the house or residen-tial circuitry.
~lectrical contact means 19 are provided by means of which electrical energy from the service ~ntrance line~ may be connected to the bus bars and ground connections are provided by a convenient bank of terminals c~uch as those illustrated by refPrence numeral ~0.
So far, everything that has been described is entirely con~
ventional and will be very familiar and well ~nown to those skilled in the art.
The essence of the invention is illustrated in Figures 3 and 4.
~ach bus bar 15 is provided, at spaced location~ along its length corresponding to the contact points for the plug fuses with silver plated copper rivets which are received in apertures formed in the bus bars.
Referring now to Figure 3, a bus bar 15 is shown in cross ~ section with the section line lying a~ong a diameter o~ an aperture :, ~
6~
22 adapted to r~ceive a rivet 21.
The aperture 22 is Eormed by a punchirlg operation with the punch being driven through the bus bar 15 in the directi.on of the arrow 23. Punching the bus har in thi.s manner provides an aperture 22 which, over a portion of its length, is provid~d with an essen-tially cylindrical wall 24 but, which is also provided~ over at least a portion of its length with a outwardly tapering wall portion 25.
This formation i5 common to the punchi.ng operation and is not, in itself, a novel phenomenon but it is important in the successful performance of the present inventionO
Each rivet 21 is provided with a cylindrical shank 26 w~ich is of a length at least as yreat and, preferably, slightly greater than the thickness T o~ the bus bar and of a diamet~r that is a force fit within at least that portion of the aperture 22 defined by the substantially cylindrical wall portion 24.
Each rivet 21 is provided with a disc-liXe head 27 of a dia-meter larger than the shank and, the free end of the shank is pro-vided with a ~onicaL re~ess ~a having a maximum diame~er slighkly less than the diameter of the shank for reasons which will be explained below.
13ach ris~et 21 is provided with a layer vf fine silver 28 that is deposited thereon and which is of ~he order of .`024 inches in ~thickness. After the layer of fine silver 28 has been deposited, the entire rivet, si:lver layer and all is further silver pla~ed.
The rivets 21 are then dri~en into the apertures 22 from the side of the bu~ bar :remote from the side from which the punching operation was performed. By inserting or driving the rivets from this side of the bùs bar, the seating of the rivets is somewhat ~acilitated in that the slightly ou~wardly flaring wall porticn 25 `
~ _ 5 _ .
'' ' provides the lead-in portion to enable the rivets to be properly seated. Furthermore, as t~e r.ivet i5 driven into th~ bus bar, some of the silver plating on the shank o~ the rivet illustrated at 29 in Figure 4 will be scraped off and will be forced into the small gap lying between ~he cylindrical shank of the rivet and the slightly outwardly flaring wall sur~ace 25 so clS to be compressed into intimate contact with both the coppar rivet ancl the copper bus bar at a loca-tion indicated by refer~nce character 30. Intimate electrical contact and heat exchange contact is, accordillgly, thereby provided between the entire shank of the rivet and the wall portion of the aperture 22 and the forceable driving of the rivet..into the bus bax also pro-vides for intimate electrical and heat exchange contact between the underside 31 of the rivet.head 27 as seen in Figure 4.
Optionally, once the rivet has been seated in the aperture in the bus bar as seen in Figure 4, it may be staked at two diametri-cally opposed points 32 and 33 as indica~ed by the arrows in Figure 4.
By this construction, a contact point is provided on the bus bar ~or each of the plug fuses shown in dotted lines at 34 in Figure 4 with the fuse tip contact 35 in intimate electrical and heat exchange contac~ with the silver plated face of the rivet head 270 ~ xtensive testing of a bus bar constructed in accordance wi~h the foregoing description in the environment of a fused domestic panelboard a~ illustrated in Figure l has enabled such a panelboard ~o meet the tempera-t;ure rise requirements of the Canadian Standards Association bulletin No. 1120 and, accordingly, provides a use~ul and sxgni~icant advance in the art.
- ' , ~.
Claims (6)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A bus bar construction for a fused residential panelboard using plug fuses comprising an elongated bus bar having apertures therein at locations corresponding to the contact points for the plug fuses and a silver plated copper rivet seated in each aperture, each rivet having a cylindrical shank at least as long as the thick-ness of the bus bar and a disc-shaped head of a greater diameter than the shank lying on the side of the bus bar adjacent the plug fuses.
2. A bus bar construction as claimed in claim 1 wherein the bus bar is formed of copper and is tin plated.
3. A bus bar construction as claimed in claim 1 wherein each rivet has a layer of fine silver deposited on the exposed face of its disc-shaped head and is subsequently entirely silver plated.
4. A bus bar construction as claimed in claim 1 in which the shank of each rivet is slightly longer than the thickness of the bus bar and is provided, at the end of the shank remote from the head, with a conical recess of a maximum diameter slightly less than the diameter of the shank so as to facilitate the staking of the rivet to the bus bar.
5. A bus bar construction as claimed in claim 3 wherein the layer of fine silver deposited on the exposed face of the head of each rivet is of the order of .024 inches thick.
6. A method of making a bus bar and plug fuse contact assembly for a fused residential panelboard comprising the steps of:
(a) punching apertures in the bus bar at spaced locations along its length corresponding to the contact points for plug fuses;
(b) driving a silver plated copper rivet having a shank at least as long as the thickness of the bus bar and a diameter that is a force fit in the aperture and having a disc-shaped head of a greater diameter than the shank into each aperture from the side of the bus bar remote from the side from which the apertures were punched.
(a) punching apertures in the bus bar at spaced locations along its length corresponding to the contact points for plug fuses;
(b) driving a silver plated copper rivet having a shank at least as long as the thickness of the bus bar and a diameter that is a force fit in the aperture and having a disc-shaped head of a greater diameter than the shank into each aperture from the side of the bus bar remote from the side from which the apertures were punched.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA306,187A CA1098610A (en) | 1978-06-26 | 1978-06-26 | Bus bar construction and method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA306,187A CA1098610A (en) | 1978-06-26 | 1978-06-26 | Bus bar construction and method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1098610A true CA1098610A (en) | 1981-03-31 |
Family
ID=4111762
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA306,187A Expired CA1098610A (en) | 1978-06-26 | 1978-06-26 | Bus bar construction and method |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1098610A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0516984A1 (en) * | 1991-06-04 | 1992-12-09 | GEC Alsthom T&D AG | Disposition for current conducting connection of two copper or aluminium conductors |
| EP2860747A3 (en) * | 2008-03-19 | 2015-07-15 | Panasonic Intellectual Property Management Co., Ltd. | Contact device |
-
1978
- 1978-06-26 CA CA306,187A patent/CA1098610A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0516984A1 (en) * | 1991-06-04 | 1992-12-09 | GEC Alsthom T&D AG | Disposition for current conducting connection of two copper or aluminium conductors |
| EP2860747A3 (en) * | 2008-03-19 | 2015-07-15 | Panasonic Intellectual Property Management Co., Ltd. | Contact device |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |