US1351043A - Electric switch and fuse box - Google Patents

Description

L. F. KRIES.

ELECTRIC SWITCH AND FUSE BOX.

APPLICATION FILED MAY 9, 1917.

III Ik L. F. KRIES.

ELECTRIC SWITCH AND FUSE BOX.

Patented Aug. 31, 1920.

2 SHEETS-SHEET 2.

APPLICATION FILED MAY 9. 1917.

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UNITED STATES PATENT OFFICE.

LAWRENCE F. KRIES, F BALTIMORE, MARYLAND, ASSIGNOR TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, OF EAST PITTSBURGH, PENNSYL- VANIA, A CORPORATION OF PENNSYLVANIA.

ELECTRIC ASWITCH AND FUSE BOX.

Specification of Letters Patent.

Patented Aug. 3 1, 1920.

Application filed May 9, 1917. Serial No. 167,398.

. To all whom t may concern:

Be it known that I, LAWRENCE F. KRIEs, a citizen of the United States, residing at Baltimore, in the State of Maryland, have invented certain new and useful Improvements in Electric Switch and Fuse Boxes, of which the following is a specification.

This invention relates to improvements in combined switch and fuse boxes, adapted for use on electric light and power circuits, for connecting and disconnecting the supply wires from the house and meter circuits, and so arranged as to prevent theft of current andto permit the customer to remove and replace fuses without danger of shock.

One purpose of the present invention is to provide means for preventing the customer from overloading his circuits, and this is accomplished by placing in series with the fuses that are accessible to the customer, load-limit fuses which are accessible only to the power company, and whichwvill blow if the customer over-fuses and overloads the house circuits. Thus, danger of overloading house wires is prevented, and as the customer must call on the power company to have the load-limit fuses replaced, the attention of the power company will thereby be called to the fact that the customer has been using fuses of greater carrying capacity than he should use.

Another purpose of the invention is to provide means for insuring the energization of the potential coil of the meter at all times when current is flowing through the load coils and house wires, thus preventing theft of current, which is sometimes accomplishedl by disabling the potential coil of the meter so that the meter wil-l not register current passing through the load coils and house wires. In order to accomplish this purpose, the circuit of the potential-.coil of the meter and all of its connections are vmade inaccessible to the customer and the circuit. is completed to the supply wires through the inaccessible load-limit fuses above mentioned, so that it is impossible tor the customer to tamper with the circuit of the potential coil, ar the latter will always. remain energized ie the switch is closed, and the loadlimit 1fuses intact.

In the accompanying drawing, which illustrates my invention, i

Figure 1 is a vertical section, on-the line 1--1 of F ig. 2, through a combined fuse and switch box having my improvements therein;

Fig. 2 is a transverse section through the same on the line 2 2 of Fig. 1;

Fig. 3 is a diagrammatic view illustrating the circuit connections of the devices shown in Figs. 1 and 2;

Fig. 4 is a section on the line 4 4 of Fig. 2, showing the customers fuseon the neutral wire short-circuited by a heavy conductor; and, ,r

Fig. 5 is a perspective view of the receptacle which carries the fuses.

For the purpose of illustration, the present improvements are shown embodied in a combined fuse and switch box of the kind shown in my Patent No. 1,126,788, in which the box or casing is provided with two compartments, one containing a switch which is inaccessible at all times, and the other containing fuses which are inaccessible while the switch is closed, but accessible when the switch is moved to open position. The present invention is applicable to various types of combined 'fuse and switch boxes having these features.

In the drawing, A represents a casing having a compartment 1, which is inaccessible to the customer at all times, and contains the supply wire terminals and the switch for connecting the supply wires with the house wires and meter, and a compartment 2,

which is inaccessible while the switch is. closed, and accessible to the customer for the purpose of removing or replacing fuses when the switch is open. The main part 3 of the casing is shown in the form of a fiat boxlike structure having an opening 3 in its front wall, and extending in front of this opening is a curved shield 4, having side walls 5. The curved wa-ll 4 forms'a cover for the fuse compartment 2. This fuse compartment has a front wall 6, a rear wall 7,

and side walls 8, forming a sector-shaped tion below that indicated in dotted lines.

In the full line position, the receptacle is closed against access by its front wall 6 and the shield 4, but when the receptacle is .receiving fuses 25.

moved downward so that its front Wall eX- tends below the shield, the interior of the receptacle is accessible. A. stop 11 is' provided for limiting the downward movement of the receptacle, and when the shield rests against said stop, the wall or partition 7 rests in a horizontal position within the shield, and the apparatus on the front of said wall is readily accessible, while the parts at the rear of said wall are inaccessi-I ble. The front wall 6 constitutes a-door, while the rearwall 7 constitutes a barrier which prevents access to the compartment 1, when the door is open.

rlhe invention is shown in connection with a three-wire system and the conductors 12, 13, and 14, leading from the source of current supply, are shown entering through the top of the casing and connected to supply wire terminals 15, mounted upon a suitable insulating base 16 on the back wall of the main part of the casing. rllhe switchmecha- `nism for connecting the supply wires with the house and meter wires is located in the compartment 1, and comprises three sets of stationary contacts 17, 18, and 19, which are adapted to be engaged by three sets of contacts 20, 21, and 22, respectively, secured to a block 23, of insulating material, which forms a partkof the wall 7, separating the fuse receptacle 2 from thecompartment 1. When the fuse receptacle is swung downwardly, the contacts on the block 23 are moved out of engagement with the stationary contacts before the door 6 passes, out of the shield 4, and when the fuse receptacle is swung to its uppermost position, the switch contacts rengage afterithe door 6 is within the shield` 0n the sides of the movable switch contacts 20 and 21 are arranged fuse terminals 24, in the form of clips for 'llhese fuses are inacf cessible to 'the customer at all times. 0n the forward side of the wall or partition 7 are provided three sets of fuse terminals 26 and 27, also in the form of clips, adapted to receive fuses 28, which are accessible toA the customer when the fuse chamber is open. Each fuse 25, in Figs.. 1 and 3, is connected in series with the vfuse 28 in front of it. As shown in Fig. 1, the base-piece 29 of the switch contact 21 is connected to thebasepiece 30 of the fuse terminal 26 by a screwfastening 31,.v so that the current may flow from the switch contact 21 through said base-pieces to the terminal 26.l The basepiece 32 of the fuse terminal 27 is connected to the base-piece 33 of the switchicontact 22 by screw connections 32a. rlhe wires 34, 34a, and 34D, leading to the house, are connected to the switch contacts 19, and two of these wires, 34 and 34", in the three-wire system shown, lead through the current coils 35 of the meter B. The potential coil 38 of the meter is connected by conductor 36 to a switch contact 18, on one side of the system, and to neutral contact 18a, as shown in the diagram, Fig. 3.

With the arrangement shown in Figs. 1 to 3, inclusive, when the. switch is closed, the circuits extend from the supply wires through the stationary switch contacts 17 to the movable switch contacts 20; thence through the loadlimit fuses 25 to the movable switch contacts 21; thence through strips 29, screw connections 31 and strips-30 to fuse terminals 26; thence through the customers fuses 28 to fuse terminals 27; thence through strips 32 and screw connections 32a and strips 33 to Amovable switch contacts 22; thence to stationary contacts 19, and thence to house wires 34-34a and 34", two of said wires, as before stated, leading through the current coils 35 of the meter. At two of the'switch contacts 21, the circuit divides, 85 a small portion of the current flowing by way of switch contacts 18 and conductors 36 and 37 through the potential coil of the meter.

The customers fuses are made accessible by rocking the fuse receptacle forwardly and downwardly, and this movement of the receptacle causes the switch in the inaccessible compartment to open before the forward wall or door 6 of the receptacle passes 95 beyond the hood 4. Hence, whenever the fuses and conducting parts in the 'chamber 2 are accessible, they are dead. When the receptacle is rocked back, to close the switch,

its forward wall 6, which constitutes a door,

passes under the hood 4 before the switchy contacts come together. Hence, all parts are inclosed while the current is on and it is impossible to steal current by connecting wires to any of the parts within the casing, or to receive a shock from such parts.

llt will be seen that the load current Hows through the fuses 425 and 28 in series. When the device is installed, the capacity of the fuses 28 will be gaged to carry the maximum 110 load which the customer is entitled to use under his contract, or the maximum load which the power company intends shall be carried by the house wires of that particular installation, and to blow and interrupt the circuits if this load is exceeded. The capacity of the. inaccessible load-limit fuses 25 will be somewhat greater than that of the fuses 28, so that thev load-limit fuses will blow if the current of the house wires materially exceeds the maximum amount which the fuses 28 will carry. lt is very common for customers of electric light and power companies to add lamps and other current consuming apparatus to the circuits without consulting the company, and when this additional load results in blowing the fuses of proper capacity for the original installation, to replace them with fuses of greater carrying capacity, thus endangering the 13@ property through possible over-heating of the wires. With the present invention, if the customer replaces the accessible fuses 28 A with fuses of greater capacity than the inaccessible load-limit fuses 25, the latter fuses will, on overload, blow and interrupt the service. As the customer cannot replace the load-limit fuses, he will have to call on the power company to attend to the matter and this will call the attention of the company to the fact that the customer is overloading thorized persons entitled to inspect all parts I of the apparatus, will remove the shield 4 and note the capacity of the overload fuses, and will also note the capacity of the customers fuses installed. The capacities of the fuses may beA noted upon the approved certiicate of inspection. Representatives of the power company, authorized to open' the boxes, may through carelessness, negligence, or otherwise, insert over-load fuses of too great capacity, after the original approval of the installation. Shouldv overheating of the wires or tires result from such overfusing, an inspection of the over-load fuses and comparison with the record made on the certificate of approval, will showwhether the representative of the power company has placed improper over-load fuses in the box. For the purpose of inspecting the over-load fuses, the cover or shield 4 is removable by removing a sealed locking pin p, and sliding the shield sidewise in the' upper guide groove Fig. 1,

as described in my prior Patent No. 1,126,788,

before referred to. This locking rod will have the usual lead seal applied by the power company to detect tampering with the box, and an additional seal may also be provided by the municipal or underwriters inspector so that the latter will have to be called upon by the power company to re-seal the box each time after it has been opened, and the municipal or underwriters" inspector will therefore be informed, at the time, of any changes in the over-load fuses.

If the customer could disconnect the potential coil of the meter and close theswitch, the current flowing through the house wires and load coils of thefmeter would not be registered as the meter would not work. To

prevent theft by cutting out the potential coil, the potential circuit is entirely concealed and inaccessible, and it is connected through the switch and the concealed loadlimit fuses 25 to the supply wires, and hence thepotential coil of the meter will always be energized while the load-limit fuses are intact and current is iowing through the load coils of the meter, because the current to the load coils also iiows through the concealed load-limit fuses before passing through the accessible customers fuses.

In some alternating current three-wire systems, one of the wires is usually grounded at the service switch, and the ground wire g is show n in Figs. 1 to 3, inclusive, attached to the switch contact 19a. This ground wire leads out of the casing through a suitable armored connection 39, and is attached in the usual way to a water or gas pipe. In the three-wire direct current system it is desirable, and, on most power distributing plants, required, that the neutral wires shall not be fused, and where this requirement is made,.a piece ofi-good conducting metal, such as c'op er tubing will be placed, as shown in Fig. 4, so as to connect the switch contact 20L with both of the contacts 21a and 22m.y Such'a connection will bridge or short-circuit the customers fuse .28 on the neutral wires and the current will flow directly through the bridge or tubing 28b from the switch contact 2Oa to contact 21'l and the potential wire 37, and to contact 22a and the house wire 34a` and ground wire g. W'ith this arrangement, the customersfuse 28a is without function, but may be used as a spare fuse which thecustomer may use on the positive or negative side of the system. The potential circuit of the meter may be connected to the neutral contact 18a and either one of the outside contacts 18; or, if the potential coils are suited to the pressure existing between the outside wires, the potential circuit may be connected to the two outside contacts 18.

In themechanism shown in the drawing, when the switch is open, all or the circuits, to the meter and house, and the ground wire leading from the switch, are cut olf from the service wires.

What I cla-im is:

1. The combination with a casing having an opening and a door for closing said opening, of customers fuses within the casing accessible when the door is open but rendered inaccessible by saidA door when the door is closed, supply wireA terminals and loadlimit fuses in. said casing, a barrier `withinthe casing rendering said terminals and load-limit fuses inaccessible through said opening in lall positions of the door,

.house wire terminals within the casing, a

switch within the casing for connecting the supply wire terminals .to the house wire terminals through said load-limit fuses and f customers fuses in series, and means operafor rendering the load-limit fuses inaccessible through said opening in all positions of the door, a switch within the casing for c0nnecting the customers fuses in series with the load-limit fuses, and means necessitating the opening of the switch prior to the opening of the door and the closure of the door prior to the closure of the switch.

3. The combination with a 'casing having an opening and a door for closing said opening, of a barrier within the casing movable with the door, customers fuses carried on one side of said barrier and accessible through said opening when the door is open, load-limit fuses carried on the other side of said barrier and rendered inaccessible by said barrier in all positions ofthe door, supply-wire terminals inaccessiblymounted in said casing, housewire terminals in said casing, and switchmembers on said barrier for connecting said supply wire terminals with said house wire terminals through said loadlimit fuses and customers fuses in series.

4C. rlhe combination with a casing having two compartments one of which has a door for permitting access to the same and the other ofwhich is inaccessible, of customers fuses within the accessible compartment, supply terminals, load terminals and a 'ground terminal in .the inaccessible compartment, and a switch in said latter compartment for connecting the ground terminal and house terminals to the supply terminals,the movable members of said switch being so operatively related to the door as to open and close therewith.

5. rlhe combination with a casing having an opening and a door therefor, of a barrier within, the casing movable with the door, customers fuses carried on 'one side of said barrier and accessible through said opening whenthe door is open, load-limit fuses car\ Latina-a tomers fuses within the casing and accessi- ,ble only when the door Ais open, supply terminals and load-limit fuses in said casing, and means within the casing rendering sai terminals and load-limit fuses inaccessible through said opening in all positions of the door, load terminals within the casing, a switch therein for connecting the customers and load-limit fuses in series with the supply and load terminals, and means necessitating the opening ofv the switch prior to the opening of the door and the closure of the door prior to the closure of the switch.

7. The combination with a casing having an opening and a door for the opening, of customers fuses within the casing accessible only when the door is open, load-limit fuses within the casing, a barrier in the casing for rendering the load-limit fuses inaccessible through said opening in all positions of the door, .a switch' within the casing, and means necessitating the opening of the switch prior to the opening of the door and the closure of the door prior to the closure of the switch.

8. The combination with a casing having an opening and a door for the opening, of customers fuses within the casing accessible only when the door is open, load-limit fuses within the casing, a switch within the cas ing, and means in the casing for rendering the load-limit fuses and the switch inaccessible through said opening in all positions of the door.

9. rl`he combination with a casing having an opening and a door for the opening, of customers fuses within the casing accessible only when the door is open, load-limit fuses Within the casing, a barrier for rendering the load-limit fuses inaccessible through said opening in all positions of the door, and means necessitating the removal of the loadlimit fuses from the circuit prior to the opening of the door.

10. The combination with a casing having an opening and a door for the opening, of

within the casing, a barrier for rendering the load-limit fuses inaccessible' through said opening in all positions of the door, and means necessitating the removal of the loadlimit fuses from the circuit prior to the opening of the door and the closure of the door prior to the inclusion of the load-limit fuses in the circuit.

ln testimony whereof l have aihXed :my

y signature.

LAVRENCE F. KRES.

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