Ground fault circuit interrupter for circuits operating with non-sinusoidal waveforms

• US 6,556,395 B1
• Filed: 07/06/2000
• Issued: 04/29/2003
• Est. Priority Date: 07/07/1999
• Status: Expired due to Term

• Current Assignee: Leviton Manufacturing Company Incorporated
• Original Assignee: Leviton Manufacturing Company Incorporated
• Inventors: Chan, David Y., Bradley, Roger M., Germain, Frantz
• Primary Examiner(s): Vu, Bao Q.
• Application Number:
  US09/610,765
• Time in Patent Office: 1,027 Days
• Field of Search: 361/42, 361/45, 361/93.1, 361/49, 361/50, 361/115
• US Class Current: 361/42
• CPC Class Codes: H02H 1/06 Arrangements for supplying operative power power supply arrangements in general G05F, H02M
• CPC Class Codes: H02H 3/33 using summation current transformers H02H3/347 takes precedence

Abstract

A device for providing ground fault protection for one or more loads in an electrical wiring system. The device includes a pickup for sensing electrical characteristics associated with conductors supplying power to the one or more loads and generating a pick up signal when predefined electrical characteristics are sensed; a ground fault detector powered using conductors that are independent of the conductors supplying power to the one or more loads, said ground fault detector being configured to receive said pickup signal, detect ground faults from said pickup signal, and generate a trigger signal when a ground fault is detected, and a power disconnect responsive to said trigger signal such that when said trigger signal is generated power to the one or more loads is disconnected. A corresponding method is also provided.

Claims

1. A device for providing ground fault protection for one or more loads in an electrical wiring system, comprising:

a pickup for sensing electrical characteristics associated with conductors supplying power to the one or more loads and generating a pick up signal when predefined electrical characteristics are sensed;

a ground fault detector powered using conductors that are independent of the conductors supplying power to the one or more loads, said ground fault detector being configured to receive said pickup signal, detect ground faults from said pickup signal, and generate a trigger signal when a ground fault is detected, and

a power disconnect responsive to said trigger signal such that when said trigger signal is generated power to the one or more loads is disconnected.

2. The device according to claim 1 further comprising a housing configured for installation in the electrical wiring system, wherein said pickup, said ground fault detector and said power disconnect are located in said housing.

3. The device according to claim 2, wherein said housing is configured and dimensioned for installation in a single gang junction box in the electrical wiring system.

4. The device according to claim 1, wherein said pickup comprises a transformer capable of sensing current differences between phase and neutral conductors supplying power to the one or more loads.

5. The device according to claim 1, wherein said pickup comprises a ground-neutral transformer capable of sensing ground to neutral faults associated with the phase and neutral conductors supplying power to the one or more loads.

6. The device according to claim 1, wherein said power disconnect comprises a relay.

7. The device according to claim 1, wherein said power disconnect comprises a solid state switch.

8. A device for providing ground fault protection for a load controlled by a phase controlled dimmer device, comprising:

line side phase and neutral connections connectable to the phase controlled dimmer device;

load side phase connection connectable to the load;

control phase and neutral connections;

a phase conductive path between said line side phase connection and said load side phase connection;

a neutral conductive path between said line side neutral connection and said load side neutral connection;

a pickup capable of monitoring current flow through said phase and neutral conductive paths and generating a pickup signal when predefined current characteristics occur;

a ground fault detector supplied power at said control phase and neutral connections, said ground fault detector being capable of detecting ground faults from said pickup signal and generating a trigger signal when a ground fault is detected; and

a power disconnect responsive to said trigger signal, such that when said trigger signal is generated said power disconnect opens at least said phase conductive path.

9. The device according to claim 8, wherein said power disconnect opens said phase and neutral conductive paths when said trigger signal is generated.

10. The device according to claim 8, wherein said power disconnect comprises a relay.

11. The device according to claim 8, wherein said power disconnect comprises a solid state switch.

12. The device according to claim 8 further comprising a housing, wherein said pickup, said ground fault detector and said power disconnect are located within said housing.

13. The device according to claim 12, wherein said housing is configured and dimensioned for installation in a junction box in an electrical wiring system.

14. The device according to claim 12, wherein said line side, load side and control phase and neutral connections comprise binding posts on an exterior of said housing.

15. The device according to claim 12, wherein said line side, load side and control phase and neutral connections comprise wire leads extending from said housing.

16. A method for providing ground fault protection for one or more loads in an electrical wiring system, comprising:

sensing electrical characteristics associated with conductors supplying power to the one or more loads and generating a pick up signal when predefined electrical characteristics are sensed;

using conductors that are independent of the conductors supplying power to the one or more loads to power a ground fault detector, said ground fault detector being, configured to receive said pickup signal, detect ground faults from said pickup signal, and generate a trigger signal when a ground fault is detected; and

disconnecting the power to the one or more loads using a power disconnect responsive to said trigger signal such that when said trigger signal is generated power to the one or more loads is disconnected.

17. A method for providing ground fault protection for a load controlled by a phase controlled dimmer device, comprising:

providing a line side phase connection and a line side neutral connection connectable to the phase controlled dimmer device;

providing a load side phase connection connectable to the load;

providing a control phase connection and a control neutral connection;

providing a phase conductive path between said line side phase connection and said load side phase connection;

providing a neutral conductive path between said line side neutral connection and said load side neutral connection;

providing a pickup capable of monitoring current flow through said phase and neutral conductive paths and generating a pickup signal when predefined current characteristics occur;

providing a ground fault detector supplied power at said control phase and control neutral connections, said ground fault detector being capable of detecting ground faults from said pickup signal and generating a trigger signal when a ground fault is detected; and

providing a power disconnect responsive to said trigger signal, such that when said trigger signal is generated said power disconnect opens at least said phase conductive path.