Resettable GFCI with Wiring Detection and Lockout
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Solution Overview
Problem
Existing circuit interrupting devices, such as GFCIs, can be improperly reset due to tripped mechanisms caused by abnormal conditions like lightning surges, and may allow reverse wiring, which compromises fault protection and leads users to believe the device is defective when it is not.
Innovation Solution
The development of resettable circuit interrupting devices that include a sensing mechanism to determine the correct wiring configuration and a reset lockout mechanism to prevent resetting if the device is not operating properly, ensuring that the line and load terminals are correctly identified and isolated from user-accessible terminals, thus preventing reverse wiring and ensuring safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a GFCI device is reset after tripping due to abnormal conditions like lightning surges, then the device can be restored to operational state, but the trip mechanism may be disabled without user knowledge, compromising safety
Solution Approach 1:
The patent implements a preliminary diagnostic action before allowing reset. The system checks whether the trip mechanism is functional before permitting the reset operation. If the trip mechanism is determined to be non-operational, the reset is blocked. This preliminary check prevents resetting a device with a disabled trip mechanism, thereby maintaining safety while allowing reset when appropriate.
2Ease of operation
If a GFCI device allows reset without checking wiring configuration, then the device is easier to operate, but reverse wiring may occur which eliminates fault protection
Solution Approach 1:
The patent performs a preliminary wiring configuration check before allowing reset. The system determines whether the device is correctly wired by checking the connection status of line and load terminals. If reverse wiring is detected, the reset operation is blocked. This preliminary verification ensures that fault protection is maintained while still allowing convenient operation when wiring is correct.
Solution Approach 2:
The patent implements a feedback mechanism that monitors the wiring configuration and provides information about the device's operational status. The system continuously checks terminal connections and uses this feedback to control the reset functionality. When incorrect wiring is detected, the feedback prevents reset, alerting the user that the device cannot be safely reset until wiring is corrected.
3Ease of operation
If a GFCI device is reset when open neutral condition exists, then power is restored, but current path through load side and person to ground is created, compromising safety
Solution Approach 1:
The patent performs a preliminary check for open neutral conditions before allowing reset. The system monitors the neutral wire connection status and determines whether an open neutral exists. If an open neutral condition is detected, the reset operation is blocked to prevent creation of dangerous current paths. This preliminary safety check maintains operational convenience when wiring is correct while preventing hazardous conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution ensures that the devices cannot be reverse wired, maintaining fault protection and preventing improper resetting, thus ensuring user safety by ensuring that the device remains in a tripped state if improperly wired or if its components are not functioning correctly.
Implementation Method 1
a sensing mechanism to determine the correct wiring configuration
Implementation Method 2
the trip mechanism used to cause the mechanical breaking of the circuit (i.e., the conductive path between the line and load sides) includes a solenoid (or trip coil)
Data Source
AI summary
The present invention relates to a family of resettable circuit interrupting devices that eliminates the need to rewire a resettable circuit interrupting device after it is installed and powered up to correct for a reverse wiring conditions.