Electricity: electrical systems and devices – Safety and protection of systems and devices – Ground fault protection
Reexamination Certificate
2001-08-24
2003-11-11
Leja, Ronald W. (Department: 2836)
Electricity: electrical systems and devices
Safety and protection of systems and devices
Ground fault protection
Reexamination Certificate
active
06646838
ABSTRACT:
BACKGROUND
1. Field
The present application is directed to a family of resettable circuit interrupting devices and systems that includes ground fault circuit interrupters (GFCI's), arc fault circuit interrupters (AFCI's), immersion detection circuit interrupters (IDCI's), appliance leakage circuit interrupters (ALCI's), equipment leakage circuit interrupters (ELCI's), circuit breakers, contactors, latching relays and solenoid mechanisms. More particularly, the present application is directed to circuit interrupting devices that include a trip portion that can break electrical conductive paths independent of the operation of a circuit interrupting portion used to sense faults and break the conductive paths when a fault is sensed, and a reset lock out portion capable of preventing the device from resetting if the circuit interrupting portion is not functioning properly or if an open neutral condition exists.
2. Description of the Related Art
The electrical wiring device industry has witnessed an increasing call for circuit breaking devices or systems which are designed to interrupt power to various loads, such as household appliances, consumer electrical products and branch circuits. In particular, electrical codes require electrical circuits in home bathrooms and kitchens to be equipped with ground fault circuit interrupters, for example. Presently available GFCI devices, such as the device described in commonly owned U.S. Pat. No. 4,595,894, use an electrically activated trip mechanism to mechanically break an electrical connection between one or more input and output conductors. Such devices are resettable after they are tripped by, for example, the detection of a ground fault. In the device discussed in the '894 patent, the trip mechanism used to cause the mechanical breaking of the circuit (i.e., the connection between input and output conductors) includes a solenoid (or trip coil). A test button is used to test the trip mechanism and circuitry used to sense faults, and a reset button is used to reset the electrical connection between input and output conductors.
However, instances may arise where an abnormal condition, caused by for example a lightning strike, occurs which may result not only in a surge of electricity at the device and a tripping of the device but also a disabling of the trip mechanism used to cause the mechanical breaking of the circuit. This may occur without the knowledge of the user. Under such circumstances an unknowing user, faced with a GFCI which has tripped, may press the reset button which, in turn, will cause the device with an inoperative trip mechanism to be reset without the ground fault protection available.
Further, an open neutral condition, which is defined in Underwriters Laboratories (UL) Standard PAG 943A, may exist with the electrical wires supplying electrical power to such GFCI devices. If an open neutral condition exists with the neutral wire on the line (versus load) side of the GFCI device, an instance may arise where a current path is created from the phase (or hot) wire supplying power to the GFCI device through the load side of the device and a person to ground. In the event that an open neutral condition exists, current GFCI devices which have tripped, may be reset even though the open neutral condition may remain.
Commonly owned application Ser. No. 09/138,955, filed Aug. 24, 1998, which is incorporated herein in its entirety by reference, describes a family of resettable circuit interrupting devices capable of locking out the reset portion of the device if the circuit interrupting portion is non-operational or if an open neutral condition exists.
SUMMARY
The present application relates to a family of resettable circuit interrupting devices that include a circuit interrupting portion, a reset portion, a reset lockout portion and a trip portion. The reset lockout portion prevents the resetting of electrical conductive paths between input and output conductors if the circuit interrupting portion used to break the conductive path is non-operational or if an open neutral condition exists. The trip portion operates independently of the circuit interrupting portion and facilitates breaking of the conductive path between input and output conductors so that the trip portion can break the conductive path whether or not the circuit interrupting portion is operating properly.
In one embodiment, the circuit interrupting device includes a housing, a first electrical conductive path disposed at least partially within said housing and capable of being electrically connected to a source of electricity, and a second electrical conductive path disposed at least partially within said housing and capable of conducting electrical current to a load when electrically continuity between said first and second electrical conductive paths is made. A circuit interrupting portion is disposed within the housing and is configured to break the continuity between the first and second conductive paths upon the occurrence of a predetermined condition. A reset portion is disposed at least partially within the housing and is configured to make electrical continuity between the first and second conductive paths. A reset lockout portion prevents the making of electrical continuity between the first and second conductive paths if the circuit interrupting portion is not operating properly (i.e., the components used to make and break electrical continuity fail or the sensing circuitry fails). A trip portion is also disposed at least partially within the housing and is configured to break the continuity between the conductive paths independently of the circuit interrupting portion operation. In this configuration, the device can be tripped whether or not the circuit interrupting portion is operating properly.
In one embodiment, the trip portion includes a trip button that is accessible from an exterior surface of the housing and a trip arm extending from the trip button. The trip arm is configured to facilitate mechanical breaking of electrical continuity between the first and second electrical conductive paths upon depression of the trip button.
The circuit interrupting portion includes a circuit interrupter that is used to facilitate making and breaking of electrical continuity between the first and second electrical conductive paths, and sensing circuitry used to sense the occurrence of a predetermined condition, such as a ground fault, an arc fault, an appliance leakage fault or an immersion fault.
In an alternative embodiment, the circuit interrupting device includes a housing, a first electrical conductor disposed at least partially within the housing and capable of being electrically connected to a source of electricity, and a second electrical conductor disposed at least partially within the housing and capable of conducting electrical current to a load when electrically connected to the first electrical conductor. A circuit interrupting portion is disposed within the housing and is configured to cause electrical discontinuity between the first and second conductors upon the occurrence of one of the predetermined conditions. A reset portion configured to reestablish electrical continuity between the first and second conductors, and a reset lockout portion is used to prevent reestablishment of electrical continuity between the conductors if the circuit interrupting portion is not operating properly. A trip portion having a trip button extending through the housing is configured to activate a trip operation in response to the trip button being manually depressed. The trip operation is independent of the circuit interrupting portion operation.
The present application also relates to a method for testing the operation of resettable circuit interrupting devices, such as the above-described family of resettable circuit interrupting devices. In one embodiment, the method involves manually activating a trip portion of the circuit interrupting device to break electrical continuity between input and output conductive paths and to enable a
DiSalvo Nicholas L.
Ziegler William R.
Leja Ronald W.
Sutton Paul J.
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