Protective device with miswire protection

• US 7,295,410 B1
• Filed: 02/22/2005
• Issued: 11/13/2007
• Est. Priority Date: 10/13/2004
• Status: Active Grant

• Current Assignee: Pass & Seymour Incorporated (Legrand SA)
• Original Assignee: Pass & Seymour Incorporated (Legrand SA)
• Inventors: Packard, Thomas N., Finlay, David A. Sr., Malley, Daniel P.
• Primary Examiner(s): Sherry; Michael
• Assistant Examiner(s): Benenson; Boris
• Application Number:
  US11/063,067
• Time in Patent Office: 994 Days
• Field of Search: 361/42, 335/18, 355/18
• US Class Current: 361/42
• CPC Class Codes: H02H 3/338 also responsive to wiring error, e.g. loss of neutral, break

Abstract

The present invention is directed electrical wiring protection device that includes a housing assembly having line terminals, load terminals, and receptacle terminals. A fault detection circuit is configured to generate a fault detection signal in response to detecting fault conditions. First interrupting contacts are configured to electrically couple the line terminals and the load terminals in a reset condition and decouple the line terminals from the load terminals in response to the fault detection signal in a tripped state. A wiring state detection circuit is coupled to at least one of the line terminals. The wiring state detection circuit is configured to generate a first wiring signal when the line terminals are connected to a source of AC power. Second interrupting contacts are configured to electrically couple the at least one receptacle load terminal to the at least one load terminal in response to the first wiring signal.

Claims

1. An electrical wiring protection device comprising:

a housing assembly including a plurality of line terminals, a plurality of load terminals, and a plurality of receptacle load terminals;

a fault detection circuit coupled to at least one of the plurality of line terminals, the fault detection circuit being configured to generate a fault detection signal in response to detecting at least one fault condition;

a first interrupting contact assembly coupled to the fault detection circuit, the first interrupting contact assembly including first interrupting contacts disposed between the plurality of line terminals and the plurality of load terminals, the first interrupting contacts being configured to electrically couple the plurality of line terminals and the plurality of load terminals in a reset condition, the first interrupting contacts being configured to decouple the plurality of line terminals from the plurality of load terminals in response to the fault detection signal in a tripped state;

a wiring state detection circuit coupled to at least one of the plurality of line terminals, the wiring state detection circuit being configured to generate a first wiring signal when the plurality of line terminals are connected to a source of AC power; and

a second interrupting contact assembly coupled to the wiring state detection circuit, the second interrupting contact assembly including second interrupting contacts disposed between at least one of the plurality of receptacle load terminals and at least one of a plurality of feed-through load terminals, the second interrupting contacts being configured to electrically couple the at least one receptacle load terminal to the at least one load terminal in response to the first wiring signal.

2. The device of claim 1, wherein the second interrupting contact assembly includes contacts disposed between a hot receptacle load terminal and a hot feed-through load terminal.

3. The device of claim 1, wherein the second interrupting contact assembly includes contacts disposed between a neutral receptacle load terminal and a neutral feed-through load terminal.

4. The device of claim 1, wherein the second interrupting contact assembly includes contacts disposed between a hot receptacle load terminal and a hot feed-through load terminal, and contacts disposed between a neutral receptacle load terminal and a neutral feed-through load terminal.

5. The device of claim 1, wherein the wiring state detection circuit further comprises a resistor electrically coupled between at least one of the plurality of line terminals and the fault detection circuit, the first wiring signal propagating through the resistor.

6. The device of claim 5, further comprising:

a mechanical linkage coupled between the resistor and the second interrupting contacts; and

a connective element mechanically coupling the resistor to the mechanical linkage, the connective element being comprised of a material having a predetermined melting temperature.

7. The device of claim 6, wherein the resistor and the connective element maintain the second interrupting contacts in an open state.

8. The device of claim 7, wherein the first wiring signal propagates through the resistor for a first predetermined period of time to thereby apply a temperature to the connective element in excess of the predetermined melting temperature, whereby the resistor is decoupled from the mechanical linkage such that the second interrupting contacts are driven into a closed state.

9. The device of claim 8, wherein the first interrupting contacts are driven to the tripped state in response to the first wiring signal propagating through the resistor.

10. The device of claim 9, wherein the first wiring signal is prevented from propagating through the resistor in the tripped state if AC power is coupled to the plurality of load terminals.

11. The device of claim 9, wherein the first wiring signal propagates through the resistor in the tripped state if AC power is coupled to the plurality of line terminals.

12. The device of claim 6, wherein the connective element includes a metallic alloy.

13. The device of claim 6, wherein the connective element includes at least one resistor body.

14. The device of claim 6, wherein the connective element includes a fuse.

15. The device of claim 6, wherein the second interrupting contacts include a fixed contact and a movable contact, the mechanical linkage being disposed in at least one or both of a neutral conductive path and/or a hot conductive path, the mechanical linkage further comprising:

a latching arm coupled to the resistor by the connective element; and

a spring member including the movable contact disposed thereon, the spring member being latched by the latching arm, whereby an air gap is disposed between the movable contact and the fixed contact before the connective element is heated to a temperature greater than or equal to the predetermined melting temperature.

16. The device of claim 6, wherein the second interrupting contacts include a fixed contact and a movable contact, the mechanical linkage being disposed in at least one or both of a neutral conductive path and/or a hot conductive path, the mechanical linkage further comprising a spring member coupled to the connective element, the spring member including the movable contact disposed thereon, the spring member being latched by the latching arm, whereby an air gap is disposed between the movable contact and the fixed contact before the connective element is heated to a temperature greater than or equal to the predetermined melting temperature.

17. The device of claim 6, wherein the second interrupting contacts include a plurality of fixed contacts and a plurality of movable contacts, the mechanical linkage further comprising:

a plunger arm coupled to the resistor by the connective element; and

a buss bar member including the movable contacts disposed thereon, an air gap being disposed between the movable contacts and the fixed contacts before the connective element is heated to a temperature greater than or equal to the predetermined melting temperature.

18. The device of claim 17, further comprising at least one spring member coupled to the buss bar member, the spring member being configured to exert a biasing force to drive the buss bar member into a closed state.

19. The device of claim 5, wherein the first wiring signal generates a differential current.

20. The device of claim 9, the wiring state detection circuit further comprises a switch configured to disable the wiring state detection circuit during manufacture of the protection device.

21. The device of claim 1, wherein the wiring state detection circuit further comprises a solenoid coupled between at least one of the plurality of line terminals and the second interrupting contact assembly.

22. The device of claim 21, wherein the solenoid is energized to thereby drive the second interrupting contacts into a closed state when an AC power source is applied to the plurality of line terminals.

23. The device of claim 22, wherein the second interrupting contacts are permanently disposed in the closed state when the AC power source is applied to the plurality of line terminals.

24. The device of claim 22, wherein the second interrupting contacts are tripped whenever the AC power source is disconnected from the plurality of line terminals.

25. The device of claim 21, wherein the wiring state detection circuit further comprises a solenoid contact coupled between the solenoid and at least one of the plurality of line terminals, the solenoid contact being configured to decouple the solenoid from the source voltage after the second interrupting contact assembly is in the closed state.

26. The device of claim 25, wherein an open or a closed state of the solenoid contact is function of the second interrupting contact assembly trip state.

27. The device of claim 25, wherein an open or a closed state of the solenoid contact is responsive to a voltage being applied to the solenoid.

28. The device of claim 1, further comprising an end-of-life mechanism configured to decouple the plurality of line terminals from the plurality of load terminals in response to an end-of-life signal from the fault detection circuit and/or interrupting contact assembly.

29. The device of claim 28, wherein the end-of-life mechanism includes contacts that decouple the hot line terminal from the hot load terminals, and/or decouple the neutral line terminal from the neutral load terminals in response to an end-of-life condition.

30. The device of claim 1, further comprising an indicator coupled between the fault detection circuit and one of the plurality of load terminals, the indicator being in an OFF state when the plurality of line terminals are connected to a source of AC power and the device is in a reset state.

31. The device of claim 30, wherein the indicator is in an ON state when the plurality of line terminals are connected to a source of AC power and the device is in a tripped state.

32. The device of claim 31, wherein the indicator is in an ON state when an end-of-life condition occurs in the reset state.

33. The device of claim 32, wherein the indicator transmits a blinking light when an end-of-life condition occurs.

34. The device of claim 32, wherein the indicator is in an OFF state when the plurality of load terminals are connected to a source of AC power and the device is in a tripped state.

35. A method for protecting a user from a fault condition in an electrical circuit, the method comprising:

providing an electrical wiring protection device that includes a housing assembly having a plurality of line terminals, a plurality of load terminals, and a plurality of receptacle load terminals, the electrical wiring protection device also including first interrupting contacts disposed between the plurality of line terminals and the plurality of load terminals;

disposing second interrupting contacts between at least one of the plurality of receptacle load terminals and at least one of a plurality of feed-through load terminals, the second interrupting contacts being initially disposed in an open state;

providing a wiring status signal configured to indicate whether the plurality of line terminals are coupled to a source of AC power; and

closing the second interrupting contacts in response to the wiring status signal indicating that the plurality of line terminals are coupled to the source of AC power.

36. The method of claim 35, wherein the second interrupting contacts remain open when the wiring status signal indicates that the plurality of load terminals are coupled to the source of AC power.

37. The method of claim 36, wherein the first interrupting contacts are configured to decouple the plurality of line terminals from the plurality of load terminals when the plurality of load terminals are coupled to the source of AC power.

38. The method of claim 35, further comprising:

sensing at least one fault condition in the electric circuit;

generating a fault condition signal in response to the step of sensing; and

tripping the first interrupting contacts in response to the fault condition signal, whereby the plurality of line terminals are decoupled from the plurality of load terminals.

39. The method of claim 35, further comprising:

disposing an end-of-life mechanism between the plurality of line terminals and the plurality of load terminals;

detecting an end-of-life condition in the protection device;

actuating the end-of-life mechanism in response to the step of detecting, whereby the end-of-life mechanism permanently decouples the plurality of line terminals from the plurality of load terminals.

40. A method for protecting a user from a fault condition in an electrical circuit, the method comprising:

providing an electrical wiring protection device that includes a housing assembly having a plurality of line terminals, a plurality of load terminals, and a plurality of receptacle load terminals, the electrical wiring protection device also including first interrupting contacts disposed between the plurality of line terminals and the plurality of load terminals;

disposing second interrupting contacts between at least one of the plurality of receptacle load terminals and at least one of a plurality of feed-through load terminals, the second interrupting contacts being initially disposed in an open state;

closing the second interrupting contacts in response to the plurality of line terminals being coupled to a source of AC power;

sensing at least one fault condition in the electric circuit;

generating a fault condition signal in response to the step of sensing; and

tripping the first interrupting contacts in response to the fault condition signal, whereby the plurality of line terminals are decoupled from the plurality of load terminals.

41. The method of claim 40, wherein the second interrupting contacts remain open when the wiring status signal indicates that the plurality of load terminals are coupled to the source of AC power.

42. The method of claim 41, wherein the first interrupting contacts are configured to decouple the plurality of line terminals from the plurality of load terminals when the plurality of load terminals are coupled to the source of AC power.

43. The method of claim 40, further comprising:

disconnecting the plurality of line terminals from the source of AC power;

opening the second interrupting contacts in response to the plurality of load terminals being coupled to a source of AC power;

reconnecting the plurality of line terminals to a source of AC power; and

closing the second interrupting contacts in response to the plurality of line terminals being coupled to the source of AC power.

44. The method of claim 40, further comprising:

opening the second interrupting contacts in response to the plurality of line terminals being decoupled from the source of AC power; and

closing the second interrupting contacts in response to the plurality of line terminals being coupled to a source of AC power.