Ground fault circuit interrupter with functionality for reset

RELATED APPLICATIONS

This application is related to provisional and non-provisional utility patent applications which are commonly owned by the assignee of this application and which are incorporated by reference. The related non-provisional utility applications are: application Ser. No. 09/251,426, by inventors Yuliy Rushansky and Howard S. Leopold, entitled “STANDOFF ASSEMBLY AND METHOD FOR SUPPORTING AN ELECTRICAL COMPONENT”, filed Feb. 17, 1999; and application Ser. No. 09/251,427, by inventors Howard S. Leopold and Yuliy Rushansky, entitled “ELECTRICAL CIRCUIT INTERRUPTER”, filed Feb. 17, 1999. In addition, this application is related to provisional patent applications which are commonly owned by the assignee of this application and which are hereby incorporated by reference. The related provisional applications are Application No. 60/167,215 filed on Nov. 24, 1999 by inventor Howard Leopold for “GROUND FAULT CIRCUIT INTERRUPTER WITH FAIL SAFE MODE,” and Application No. 60/210,015 filed on Jun. 8, 2000 by inventors Gunter Gallas and Howard Leopold for “GROUND FAULT CIRCUIT INTERRUPTER WITH FUNCTIONALITY FOR RESET.”

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to an error detection circuit interrupter device that includes a detection circuit for determining whether an error has occurred in an exterior circuit and includes an interrupter device for stopping current flow to the exterior circuit when an error has been detected. More particularly, the invention relates to a GFCI that has a reset device which utilizes a test current to actuate a bistable latching relay and reset the tripped GFCI - thus testing the functionality of the GFCI and resetting the GFCI simultaneously. Furthermore, the invention relates to a ground fault circuit interrupter device (GFCI) with a fail safe mode, wherein the GFCI is incapable of being reset after a trip if any of its key electrical components malfunction or are not working.

2. Description of the Related Art

Fault or error detection devices are well known in the art to provide additional safety for electrical components. A specific type of fault or error detection device is known as a GFCI device. In operation, a GFCI type device supplies electricity to an exterior circuit and opens an outlet circuit when a ground fault occurs in the exterior circuit, i.e., when a portion of a circuit that is plugged into the outlet becomes grounded. For example, if a hair dryer is negligently dropped into a bathtub, electricity may flow from the hair dryer circuit to ground through the bathtub water. A person might be part of the current path to ground. An electrical outlet provided with a GFCI device would detect such a ground fault and, almost instantaneously, open the outlet circuit to prevent current from flowing from the hair dryer circuit to ground. Although the GFCI device is described above as being associated with an outlet, the typical GFCI device can be associated with other different types of electrical junctures.

Conventional GFCI devices include a detection circuit that compares the current leaving the outlet circuit to the current returning to the outlet circuit. When there is a pre-set differential between the leaving and returning outlet currents, the GFCI opens the outlet circuit and indicates that a ground fault has occurred. The detection circuit can be constructed in a number of different ways, including providing a differential transformer for sensing the imbalance in the current flow. In addition, there are many different structures that have conventionally been used to open the circuit once the ground fault has been detected. For example, some conventional GFCI devices use a trip coil to open the outlet circuit. A test and reset button are also typically provided on the GFCI device for testing whether the device is functioning properly and for resetting the device after testing or after the device has been tripped. Conventional GFCI devices are often complicated structures that require sophisticated manufacturing processes to ensure that they work properly and safely. Conventional GFCI devices, as well as the GFCI device in U.S. application Ser. No. 09/251,427, do not have a structure for ensuring that the GFCI device cannot be reset when one or more key electrical components, such as the transformer, integrated circuit (IC), solenoid, and solenoid controlling devices are not operable. For example, for the GFCI device of application Ser. No. 09/251,427, if the GFCI unit trips because of a ground fault, the unit can be manually reset by depressing the reset button. If one of the key electrical components is damaged due to the ground fault or by any other means, the GFCI can still be reset so that electricity would be provided to the electrical outlet. In this case however, the GFCI will no longer be able to detect another ground fault and thus will no longer be able to stop current flow to the exterior circuit. Several other drawbacks also exist in other conventional GFCI devices, including high manufacturing cost, poor reliability, poor endurance, potential safety concerns due to excessive heat generation and/or poor reliability, and general aesthetic and ergonomic drawbacks.

SUMMARY OF THE INVENTION

An object of the invention is to provide a fault/error detection device that is economic to manufacture, requires as few parts as possible and operates at a high level of reliability. Another object of the present invention is to provide a GFCI device that is capable of being reset after a trip only if the GFCI circuit is operational. Another object of the invention is to provide a GFCI device that is incapable of being reset if any of the key electrical components become inoperable. Another object of the invention is to provide a GFCI device that is simple to manufacture and includes as few parts as possible while also providing the structural stability necessary for the device to be tested on a regular basis. Another object of the invention is to provide a GFCI device that includes a test light indicator that will indicate when the GFCI device has been tripped, whether the GFCI device is wired correctly.

To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described, the GFCI device includes a switch connected to a current sensing device. The current sensing device is capable of determining whether the outflow of current is different from inflow, and upon sensing a difference between outflow current and inflow current (sensing a possible ground fault), outputting an electrical signal to a bistable latching relay trip mechanism which then opens the main switch and prevents current from flowing through the GFCI. The device includes a reset switch that sets up a test condition for the GFCI device. If the reset switch is activated and test conditions indicate that the GFCI is functioning properly, an electrical signal is provided to the bistable latching relay switch which then closes the main switch and permits current to pass through the GFCI.

In accordance with another aspect of the invention, a GFCI device with a fail safe mode prevents restoration of current flow through a first circuit when a component of the GFCI device is malfunctioning or otherwise inoperable. The ground fault circuit interrupter device can include a housing, a substructure located in the housing, a ground fault detector located on the substructure and capable of detecting whether a ground fault has occurred in the first circuit, a current path structure located on the substructure and having a first end terminating at an input connector and a second end terminating at an output connector. The current path structure preferably includes a single electrical splice. A pair of contact points can be located in the current path structure and displaceable from each other to open the current path structure and cause current to stop flowing in the first circuit when the ground fault detector detects that a ground fault has occurred. The means for displacing the contact points can include a latch biased towards a predetermined position by a hairspring at one end and an armature within a solenoid at another end, where displacement of the armature in a predetermined direction causes displacement of the latch to ultimately allow displacement of the contact points.

In accordance with another aspect of the invention, the GFCI device can include a thermally activated part that, upon being heated by an overheated solenoid coil, moves into a position to block the ability for the GFCI device to be reset. The GFCI reset ability can be blocked by preventing normal movement of the latch or preventing normal movement of the armature. The overheated solenoid is an indication that the GFCI device is malfunctioning and therefore should not be permitted to be reset. The thermally activated part can be, for example, a thermocouple connected to an electrical switching device that moves a locking mechanism into contact with either the latch or the armature when a predetermined “solenoid overheating” temperature is sensed by the thermocouple.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of the specification, illustrate one embodiment of the invention and together with the written description serves to explain the principles of the invention. In the drawings:

FIGS. 1A and 1B

are first and second perspective views of a GFCI device embodying the principles of the invention;

FIG. 2

is an exploded view of the GFCI device of

FIGS. 1A and 1B

;

FIGS. 3A and 3B

are exploded and unexploded perspective views, respectively, of the PC board assembly as shown in

FIG. 2

;

FIG. 4

is an isometric view of the back of the top housing cover as shown in

FIG. 1A

;

FIG. 5

is an isometric view of the back of the bottom housing cover as shown in

FIG. 1B

;

FIGS. 6A and 6B

are isometric views of the hot current path and neutral current path, respectively, of the GFCI device as shown in

FIG. 2

;

FIGS. 7A-7D

are top, first isometric, bottom, and second isometric views of the middle housing as shown in

FIG. 2

;

FIGS. 8A-8D

are first and second isometric views of the hot output terminal and first and second isometric views of the neutral output terminal, respectively, of the GFCI device of

FIG. 2

;

FIGS. 9A and 9B

are isometric views of the hot contact arm and the neutral contact arm, respectively, of the GFCI device as shown in

FIG. 2

;

FIG. 10A-10D

are first and second perspective views of the neutral input terminal and first and second perspective views of the hot input terminal, respectively, of the GFCI device as shown in

FIG. 2

;

FIG. 11

is an isometric view of the test button of the GFCI device as shown in

FIG. 2

;

FIGS. 12A and 12B

are first and second isometric views, respectively, of the latch block assembly as shown in

FIG. 2

;

FIG. 13

is an exploded view of the latch block assembly shown in

FIG. 12

;

FIGS. 14A and 14B

are first and second isometric views, respectively, of the solenoid and solenoid bobbin as shown in

FIG. 2

;

FIGS. 15A and 15B

are first and second isometric views, respectively, of the solenoid clip as shown in

FIG. 2

;

FIGS. 16A and 16B

are first and second isometric views, respectively, of the transformer boat as shown in FIG.

2

.

FIG. 17

is a perspective drawing of the circuit desensitizing switch for the GFCI device as shown in

FIGS. 2

;

FIGS. 18A-18D

are sequential skeleton drawings of the trip/reset structure for the GFCI device as shown in

FIG. 2

;

FIGS. 19A-19C

are schematic views of the GFCI device in a “reset”, “trip due to a ground fault” and “electronic component malfunction” state, respectively; and

FIG. 20

is a flow chart of an embodiment of the invention including a bistable latching relay to test the functionality of the GFCI during reset operations.

FIG. 21

is a block diagram of another embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the present preferred embodiment of the invention, an example of which is illustrated in the accompanying drawings.

FIG. 1A

shows a GFCI device

1

that is constructed in accordance with the principles of the invention. The GFCI device can have a top housing cover

100

that is constructed of a size and shape that is consistent with industry standards for an electrical outlet. Preferably, the device includes two sets of receptacle openings for receiving standard plugs. A test/reset aperture can be located along a mid-line of the top housing cover

100

and include a test button

801

and reset button

802

located therein. A light aperture

108

can also be located on the mid-line of the top housing cover

100

to enclose a light for indicating whether the GFCI device has been tripped due to either a ground fault detection or a test of the device. The light can also indicate whether the GFCI device has been correctly wired and whether the key electrical components are functioning properly.

Top and bottom angled indicia surfaces

101

can be provided on either side of the midline and include indicia thereon. The indicia can include numerals, letters, symbols or other markings that can be viewed from the exterior of the GFCI device and which preferably provide an instructional message to a viewer. In the embodiment depicted in

FIG. 1A

, the indicia comprise the terms “test” and “reset” to instruct a viewer of the function of the buttons located adjacent the indicia surfaces. The angled indicia surfaces are preferably sloped at a 45° angle with respect to the substantially planar face surface

107

of the top housing cover

100

so that the indicia can be read from above and below the GFCI device. Accordingly, a user can read the indicia on the angled indicia surfaces

101

regardless of the orientation of the GFCI device when installed. Furthermore, it should be appreciated that this preferred configuration de-emphasizes the visual appearance of indicia on the top indicia surface and emphasizes indicia located on the bottom indicia surface when viewed from above, e.g., when the device is installed in a wall.

A mounting strap

920

extends from either side of the top housing cover

100

for attaching the GFCI device to a wall box. Indents

103

can be provided on either side of the top housing cover

100

to facilitate connection to electrical wires.

FIG. 1B

shows an isometric view of the bottom housing cover

200

which is attached to the top housing cover

100

via screws inserted through the connection holes

201

in the bottom housing

200

. Neutral connection holes

202

and hot connection holes

203

are located in the bottom housing cover

200

to provide an alternate connection for input wires onto the GFCI circuit. In addition, neutral connection holes

204

and hot connection holes

205

are located on the bottom housing cover

200

to provide an alternate attachment structure for output wires leading from the GFCI circuit. A wide pathway

206

can be located at one end of the periphery of the bottom housing cover

200

to facilitate attachment of a U-shaped wire connector to the grounding screw of the GFCI device. Indents

208

may also be provided on the bottom housing cover

200

and aligned with the indents

103

of the top housing cover

100

to provide clearance for U-shaped wire attachment structures for input and output wires.

As shown in

FIG. 2

, the top housing cover

100

and the bottom housing cover

200

encase the GFCI components and circuitry including a middle housing

300

and circuit board

950

therebetween. The middle housing

300

is located above the circuit board

950

and adjacent the top housing cover

100

. The circuit board

950

rests adjacent the bottom wall of the bottom housing cover

200

. The middle housing

300

can be a one piece molded structure that has a plurality of ribs thereon to locate and stabilize the GFCI circuit components. A mounting strap

920

can be sandwiched between the top housing cover

100

and the middle housing

300

and extend from either end of the GFCI device so that the GFCI device can be mounted to a conventional wall box.

The GFCI circuitry as shown in

FIG. 2

includes a transformer device for detecting a ground fault, a solenoid trip device for causing both current pathways of the GFCI device to open, and a test/reset structure for periodically testing the GFCI device and for resetting the GFCI device after it has been either tested or tripped.

FIGS. 3A and 3B

depict an exploded view and an isometric view, respectively, of the electronic components

951

and other various components that are located on the circuit board

950

of the GFCI device. The electronic components

951

include resistors, capacitors and other well known electronic circuit components for comprising a GFCI circuit. The electronic components

951

can be attached to the circuit board

950

via any well known attachment method, e.g., by soldering. The circuit board

950

can include clip apertures

952

and pivot apertures

953

for attaching the transformer boat

400

and the solenoid bobbin

700

quickly and easily with lock/alignment pins and clips located on the base of each of the transformer boat

400

and solenoid bobbin

700

.

The test light

901

can be raised from the circuit board

950

by the standoff

900

. The standoff

900

is preferably a two-piece snap together structure as described in applicant's co-pending patent application filed on same date and incorporated herein by reference.

Elements of the current path can be attached to the circuit board at a hot attachment point and a neutral attachment point. Specifically, hot contact arm

520

and hot input terminal

550

can be soldered together and to the circuit board

950

at a location underneath the transformer boat

400

. Likewise, the neutral contact arm

620

and neutral input terminal

650

can be soldered together and to the circuit board

950

at a location underneath the transformer boat

400

and adjacent to the hot attachment point. Accordingly, electrical power can be supplied to the electronic components

951

and all other electronic devices located on the circuit board

950

via the hot input terminal

550

and neutral input terminal

650

.

As shown in

FIG. 4

, the top housing cover

100

can include tapped or self tapping attachment holes

102

located at the corners of the top housing cover

100

for screw connection to the bottom housing

200

. Contact cavities

104

are shown located in the central portion of the top housing cover

100

for sealing and protecting the area in which contacts are located in the hot and neutral current paths. Test reset aperture

105

can be configured as a long, narrow rectangular opening in the central portion of the top housing cover

100

. The test/reset aperture

105

permits the test button

801

and reset button

802

to be contactable from outside of the top housing cover

100

.

A reset pin guide

106

can be formed as part of the back surface of the top housing cover

100

to stabilize and guide the motion of the reset button

802

and shaft

804

in a linear path when they are actuated.

Light aperture

108

can be located adjacent the test/reset aperture

105

for convenient viewing. The test light

901

is aided by the standoff

900

to extend from the circuit board

950

and into the light aperture

108

.

Ground hole

110

and slots

109

are shown arranged in the North American standard configuration for household electrical outlets. Although not shown, other configurations for the ground hole

110

and slots

109

are well known for complying with other types of electrical plugs as appropriate in various area of the world and for various applications.

As shown in

FIG. 5

, the bottom housing

200

can be a unitary one piece structure that is generally rectangular in shape and includes connection holes

201

located at each corner. The connection holes

201

are in alignment with the attachment holes

102

in the top housing cover

100

for connecting the top and bottom housing covers

100

,

200

by a screw, nail or other fastening device.

The bottom housing

200

of the GFCI device can be configured with several different input and output connection options. In particular, indents

208

can be provided at the sides of the bottom housing

200

to facilitate connection between a U-shaped connector on an input wire to a screw/face terminal connection

961

provided on one of the current pathways of the GFCI circuitry. In addition, bottom housing

200

can be provided with neutral input connection holes

202

, hot input connection holes

203

, neutral output connection holes

204

and hot output connection holes

205

. The connection holes

202

-

205

permit bare electrical lines access to the GFCI circuitry. Specifically, a bare wire inserted into one of the connection holes

202

-

205

can be guided to an area between a connection face plate

963

and its associated wire connector surface, e.g., wire connector

508

,

551

,

608

or

651

. After insertion, the bare wire can be clamped into connection with one of the current pathways by turning a screw of a screw/face terminal to cause the connection face plate

936

to close onto and clamp the bare wire between the connection face plate

963

and a wire connector

508

,

551

,

608

or

651

. The connection face plate

963

can include horizontal grooves therein to prevent a bare wire connected thereto from slipping out of connection with the connection face plate

963

. A bare wire connection can be made alternatively or in addition to the connection of a U-shaped wire terminal to the screw/face terminals

961

located at the sides of GFCI housing.

The screw/face terminals

961

can be situated in the bottom housing

200

such that they can be connected to either a U-shaped connector on the end of a wire at indent

208

or to a bare wire that is inserted into one of the connection holes

202

-

205

. The U-shaped wire terminal can be clamped between the screw head of the screw/face terminal

961

and the outer surface of one of the wire connectors

508

,

551

,

608

or

651

.

FIGS. 6A and 6B

show the hot and neutral current pathway structures, respectively, of the GFCI device.

FIG. 6A

depicts the various structures that make up the hot current pathway for the GFCI device and shows their relative position as assembled. The hot current pathway can consist of a hot input terminal

550

, hot contact arm

520

two contacts

501

and

521

and a hot output terminal

500

. The hot input terminal

550

can be configured to be attachable to an electrical wire for receiving positive (hot) current into the current pathway. The hot input terminal

550

can be attached to the hot contact arm

520

by soldering or the like. Additionally, both the hot input terminal

550

and hot contact arm

520

can be anchored to the circuit board

950

by the same solder connection that connects the two structures together. The hot contact arm

520

can be figured to include a contact stem

522

that extends through the center of a transformer coil

408

located in the transformer boat

400

when assembled. Current passing through the contact stem

522

is compared by the transformer coil

408

to the current returning through a similar contact stem

622

located on the neutral contact arm

620

. In accordance with the laws of physics, an electrical current will be induced in the transformer coil

408

when there is a differential between the current flows in contact stems

522

and

622

. Once a predetermined current is induced in the transformer coil

408

, a ground fault will be indicated by the GFCI device and the current paths will be opened as explained later.

The hot contact arm

520

can be separably connected to the hot output terminal

500

via a pair of contacts

501

,

521

. Contact

521

can be located on a cantilevered arm portion the hot contact arm

520

and contact

501

can be located on a stationary arm of the hot output terminal

500

. Accordingly, a downward force applied to the cantilevered arm portion will force the contact

521

out of contact with the contact

501

located on the hot output terminal

500

to open the hot current pathway. The hot output terminal

500

can be separably connected to the hot contact arm

520

as explained above and can include two conventional spring type electrical receptacle contacts

504

and a wire connector

508

. The wire connector

508

and receptacle contacts

504

can be connected to an outside circuit, e.g., to an appliance, other electrical device or other electrical receptacle.

As shown in

FIG. 6B

, the neutral current pathway structure can consist of a neutral input terminal

650

, a neutral contact arm

620

, a pair of contacts

601

,

621

and a neutral output terminal

600

. The neutral input terminal

650

can be attached to an electrical wire at one end and soldered to the circuit board

950

and the neutral contact arm

620

at the opposite end. The neutral contact arm

620

includes a contact stem

622

that can be positioned adjacent the contact stem

522

of the hot contact arm

550

and through the transformer coil

408

to allow ground fault detection as explained above. Contact

621

can be located at a distal end of a cantilevered arm portion of the contact arm

620

and contact

601

can be located on a stationary arm of the neutral output terminal. The cantilevered arm portion is configured such that contact

621

will separate from contact

601

when a downward force is applied to the cantilevered arm portion of the contact arm

620

. Accordingly, the neutral current pathway can be opened by a linear downward force applied to the cantilevered arm portion. In addition, the hot contact arm

520

and neutral contact arm

620

can be located adjacent each other when assembled into the GFCI housing such that a single structure, e.g., latch block assembly

810

, can provide the downward linear force necessary to simultaneously open both the hot and neutral current pathways. The neutral output terminal

600

can be separably connected to the neutral contact arm

620

at contact point

601

as explained above. The neutral output terminal

600

also includes two conventional spring type electrical receptacle contacts

604

and a wire connector

608

for connecting a neutral electrical conductor between the GFCI device and an appliance or other electrical device or receptacle.

As shown in

FIGS. 7A-7D

the middle housing

300

can be molded from a unitary piece of plastic and be configured to fit within and be clamped between the top housing cover

100

and bottom housing cover

200

. The middle housing

300

is preferably a different color as compared with the top housing

100

and bottom housing

200

to more clearly indicate where electrical wires can be connected to the GFCI device. For example, the middle housing

300

is preferably blue while the top housing

100

and bottom housing

200

are preferably white and grey, respectively. A pair of contact arm through holes

306

can be provided in the central area of the middle housing

300

so that the far end of the cantilevered portions of the hot and neutral contact arms

520

and

620

, can pass through the middle housing

300

allowing each pair of contacts

501

,

521

and

601

,

621

to contact each other. Thus, the middle housing

300

protects the circuit board

950

from any sparking that may occur between pairs of contacts

501

,

521

and

601

,

621

when they are separated from or contacted to each other.

The top portion of the middle housing

300

can be configured to align the hot output terminal

500

and the neutral output terminal

600

and to electrically separate both of these structures from each other and from the components located on the circuit board. The hot output terminal

500

and neutral output terminal

600

can be located between the top housing cover

100

and the middle housing

300

such that a conventional plug will have access to the hot output terminal

500

and neutral output terminal

600

when inserted through slots

109

in the top housing cover

100

.

A test resistor through hole

304

in the central portion of the middle housing allows a test resistor to pass therethrough. As will be explained in more detail later, the test resistor allows the GFCI device to be tested by simulating a ground fault by diverting current through the test resistor from the hot output terminal and eventually to the neutral input terminal through the circuit board

950

. A light standoff through hole

302

can be located in the middle housing

300

to support the standoff

900

as it extends from the circuit board to the top housing cover

100

. Likewise, a reset shaft through hole

320

can be placed in a central area of the middle housing

300

to permit the reset shaft

804

to pass therethrough and to guide the reset shaft

804

along a linear path. In addition, the reset shaft through hole

320

includes a countersunk portion on the bottom side of the middle housing, as shown in

FIG. 7C and 7D

, that allows a latch block

820

and latch block actuation spring

812

to reside therein. Accordingly, the reset shaft through hole structure guides the latch block

820

along the same linear path as taken by the reset shaft when moved.

A hot output terminal throughway

316

and a neutral output terminal throughway

318

can be located at either side of the middle housing to allow the U-shaped wire connectors

508

and

608

to pass through the middle housing

300

and be exposed at either side of the GFCI device for connection to electrical wires. A test button guide way

322

can be located in the top portion of the middle housing

300

for guiding the test button

801

along a linear path and into contact with the test switch arm

502

of the hot output terminal

500

. The test button

801

can be located above and guided within the top portion of the middle housing

300

above the test resistor through hole

304

.

The bottom portion of the middle housing

300

can include alignment holes

324

that mate with alignment posts

419

located on the transformer boat

400

. Alignment between all of the components of the GFCI device is important to ensure that the hot and neutral contacts

501

,

521

and

601

,

621

, respectively, remain in contact with each other when the GFCI device is in its “reset position” and to ensure that the contacts will be out of contact with each other when the GFCI device is in its “tripped position.” A transformer boat indent

308

and a solenoid bobbin indent

314

can be provided in the bottom portion of the middle housing

300

to secure and align the transformer boat

400

and solenoid bobbin

700

. A hot contact arm indent

310

and a neutral contact arm indent

312

can be separated from each other by a separation wall

326

to provide alignment structures for the hot and neutral contact arms

520

and

620

, respectively, to reside in. The separation wall

326

also electrically insulates the contact arms

520

and

620

from each other.

Screw/face supports

327

can extend from the bottom of the middle housing

300

and into the central opening of the U-shaped wire connectors

551

and

651

located on the hot input terminal

550

and neutral input terminal

650

, respectively. The screw/face supports

327

serve to retain the screw/face terminals

961

in a general area and provide support when the screw/face terminals

961

are used to lock down an electrical wire.

As shown in

FIGS. 8A-8D

, the hot output terminal

500

and neutral output terminal

600

can each be constructed as a one-piece structure that is made from an electrically conductive material such as brass. The hot output terminal

500

can include two receptacle contacts

504

that are disposed adjacent slots

109

in the top cover housing

100

when assembled. As shown in

FIG. 8A

, the receptacle contacts

504

are standard spring receptacle contacts that are adapted to receive a standard 120V North American plug. However, different receptacle contacts can be used depending on the location and application of the GFCI device. U-shaped wire connector

508

extends from one end of the hot output terminal such that, when assembled, it will be located at and accessible from the side of the GFCI device for attachment to an electrical wire. A contact

501

configured for connection to a contact

521

on the hot contact arm

520

can be located on an arm that extends laterally from the hot output terminal

500

. The extended arm portion of the hot output terminal

500

is relatively short and rigid such that the attached contact

501

remains stationary with respect to the hot output terminal

500

and the middle housing

300

in which the hot output terminal

500

resides.

A test switch arm

502

can be provided as an integral lateral extension from the hot output terminal

500

. The test switch arm

502

can be configured to reside over the test resistor through hole

304

and under the test button

801

when assembled in the GFCI device. The test switch arm

502

is also of such a length and rigidity that depression of the test button

801

from outside the GFCI device will cause the test button

801

to contact and bend the test switch arm

502

into contact with a test resistor located in the test resistor through hole

304

of the middle housing

300

. Current that flows from the hot output terminal

500

through the test switch arm

502

to the test resistor will (if the GFCI device is operating correctly) cause the GFCI device to indicate a ground fault has occurred and subsequently trip the GFCI device to open the current pathways.

The neutral output terminal

600

can also include two receptacle contacts

604

constructed in a similar fashion as are receptacle contacts

504

of the hot output terminal

500

. A wire connector

608

can also be provided on the neutral output terminal

600

. A contact

601

can be provided on a relatively short and rigid extension arm on the neutral output terminal

600

for connection to a contact

621

located on the neutral contact arm

620

.

As shown in

FIGS. 9A and 9B

, hot contact arm

520

and neutral contact arm

620

can each be configured as a unitary structure that is basically a mirror image of each other. The hot contact arm

520

can include a contact stem

522

that is designed to extend through the center of transformer coils

408

in the transformer boat

400

. A distal end of the contact stem

522

can be soldered, welded or otherwise electrically connected to both the circuit board

950

and connecting tab

552

of the hot input terminal

550

. The opposite end of the contact stem

522

includes a stop tab

526

that extends from a side of the contact stem

522

for abutting against the transformer boat

400

. The stop tab

526

ensures the correct insertion depth of the contact stem

522

into the circuit board and correctly aligns the hot contact arm

520

with the transformer boat

400

and GFCI circuitry. The hot contact arm

520

includes a series of bends at its middle portion to navigate around the transformer boat structure. Another stop tab

526

and an alignment post

524

can extend into transformer boat

400

and are located in the middle portion of the contact arm

520

to align the contact arm

520

within the GFCI device. A cantilevered arm portion extends from the middle portion and has a through hole at its distal end for connection to contact

521

. When assembled in the GFCI device, the cantilevered arm portion extends through the middle housing such that contact

521

is normally in contact with contact

501

of the hot output terminal

500

. In addition, the cantilevered arm portion is of such a length and dimension that it can be forcibly flexed about a position adjacent to the alignment post

524

. Accordingly, contact

521

can be in contact with contact

501

when in the reset position and forcibly flexed away from and out of contact with contact

501

when in the tripped position. The stop tabs

526

and alignment tab

524

ensure that the contact arm

520

is positioned correctly so that the contacts

501

and

521

will be in contact and out of contact in their reset and tripped positions, respectively. In particular, alignment tab

524

is designed to extend into an alignment tab receptacle

422

in the transformer boat

400

at a depth set by stop tab

526

to secure the position of the contact arm

520

with respect to the transformer boat

400

. In addition, the alignment tab

524

and stop tab

526

create an anchor point from which the cantilevered arm portion can flex.

The neutral contact arm

620

can include similar structures that perform relatively identical functions as compared to the hot contact arm

520

. Moreover, neutral contact arm

620

can include stop tabs

626

and alignment tab

624

for alignment with the transformer boat

400

and for providing an anchor point for a cantilevered arm portion of the neutral contact arm

620

. Contact stem

622

is designed to extend through the transformer boat

400

adjacent to the contact stem

522

of the hot contact arm

520

and be similarly electrically attached to both the circuit board

950

and the corresponding neutral input terminal

650

at a distal end of the contact stem

622

. A contact

621

can be located at a distal end of the cantilevered portion of the neutral contact arm for connection to contact

601

of the neutral output terminal when in the reset position, and for forcible separation from the contact

601

when in the tripped position.

As shown in

FIGS. 10A-10D

, the neutral input terminal

650

and hot input terminal

550

can each be a one-piece unitary structure made from electrically conductive material. The neutral input terminal

650

can be an approximate mirror image of the hot input terminal

550

and include a U-shaped wire connector

651

, a connection tab

652

and a pair of mounting tabs

654

. The mounting tabs

654

and connection tab

652

can be assembled onto the circuit board

950

such that they extend through and are soldered onto the circuit board

950

. Connection tab

652

can also be soldered to the contact stem

622

of the neutral contact arm

620

such that electrical current can pass between the neutral contact arm

620

and neutral input terminal

650

. The U-shaped wire connector

651

can be arranged at an approximate 90 degree angle with respect to the base of the neutral input terminal

650

so that, when installed, the wire connector

651

is located at and accessible from a side of the GFCI device. The location of the wire connector

651

provides easy connection to an electrical wire via the screw/face terminal

961

.

As stated above, the hot input terminal

550

can be constructed as an almost identical mirror image of the neutral input terminal

650

. Specifically, the hot input terminal

550

can include a U-shaped wire connector

551

that is configured at a 90 degree angle with respect to a base portion of the hot input terminal

550

. Mounting tabs

554

and connecting tab

552

can extend from the bottom of the base portion for electrical connection to the circuit board

950

via soldering or other known permanent electrical connection. The connection tab

552

can also be electrically connected to the contact stem

522

of the hot contact arm to create a current pathway therebetween.

As shown in

FIG. 11

, test button

801

can be formed of a single-piece non-conductive material, for example, plastic. The test button

801

is design to have a push surface (as shown in

FIG. 1A

) that extends from the test/reset aperture

105

in the top housing cover

100

. The test button

801

can be depressed by a user to cause the GFCI circuitry to simulate a ground fault detection, thereby testing whether the GFCI device is working properly. Stop flanges

808

can be located at either side of the test button

801

to abut a side of the test/reset aperture

105

and prevent the test button

801

from being removed from the top housing cover

100

. A test switch arm contact surface

803

can be located below the push surface of the test button

801

and at the end of an extension supported by guide rib

809

. The contact surface

803

can be designed to contact the test switch arm

502

of the hot contact arm such that the resiliency of the test switch arm

502

keeps the test button in a protruded state from the test/reset aperture

105

in the top housing cover

100

. In addition, when the test button

801

is depressed, the contact surface

803

can be situated such that it forces the test switch arm

502

to flex downward and contact a test resistor located in the test resistor throughway

304

to simulate a ground fault and test whether the GFCI device is operating properly. The test button

801

can be guided along a linear path during depression by guide rib

809

acting in conjunction with the test button guide way

322

in the middle housing

300

.

As shown in

FIGS. 12A

,

12

B and

13

, latch block assembly

810

can include two major components: a latch block

820

and a latch

840

. The latch block assembly

810

works in conjunction with other elements of the GFCI device to perform various functions, including retaining the reset shaft

804

in its “reset” position, or, causing the contacts

501

,

521

and contacts

601

,

621

to decouple from each other to open the GFCI circuitry when a ground fault is detected or if a key electronic component malfunctions. The latch block

820

can be T-shaped with arms

821

that extend from opposite sides of a main body portion

826

and a shield tube