Circuit Breaker Lug Wire Indicator for Full Wire Insertion
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Solution Overview
Problem
Existing residential circuit breakers lack a clear indication that panel wires are fully inserted into the lug, leading to potential arcing connections, thermal overload conditions, or loss of power due to partial insertion, which is not visually discernible during installation.
Innovation Solution
A lug wire indicator with an extended indicator flag and a return spring positioned below the lug provides a visual confirmation of full wire insertion before tightening the pressure screw, utilizing space below the lug to avoid increasing the breaker's overall length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If the indicator flag is positioned directly behind the lug to provide wire insertion indication, then the visual indication is clear, but the overall length of the circuit breaker must be increased to accommodate the indicator mechanism
Solution Approach 1:
The indicator flag is repositioned from a horizontal arrangement behind the lug to a vertical arrangement below the lug. This dimensional change allows the indicator mechanism to fit within the existing circuit breaker envelope without increasing the overall length, while still providing clear visual indication of wire insertion status.
Solution Approach 2:
Instead of extending the indicator mechanism horizontally behind the lug (traditional approach), the patent inverts the arrangement by positioning the indicator flag vertically below the lug. This inversion allows the same functional indication to be achieved within the constrained length of existing circuit breaker designs.
2Loss of information
If the circuit breaker envelope is increased to accommodate the indicator mechanism behind the lug, then the wire insertion indication is provided, but the overall cost of manufacturing and packaging increases
Solution Approach 1:
By repositioning the indicator mechanism to a vertical orientation below the lug, the patent eliminates the need to increase the circuit breaker envelope dimensions. This maintains compatibility with existing manufacturing processes, test fixtures, and packaging (cardboard cartons and clamshells), thereby avoiding increased manufacturing costs.
Solution Approach 2:
The indicator mechanism is designed to work within the existing circuit breaker envelope, making the design universally compatible with current manufacturing and packaging infrastructure. This multi-functional approach allows the indicator to serve its purpose without requiring separate tooling or packaging modifications.
3Ease of manufacture
If the indicator mechanism is simplified to reduce cost, then manufacturing is easier, but the visual indication may become less clear or reliable
Solution Approach 1:
The indicator flag utilizes color changes to provide clear visual indication of wire insertion status. The flag displays different colors or color patterns depending on whether the wire is properly inserted, maintaining high visibility and clarity while using a simple mechanical mechanism that is easy to manufacture.
Solution Approach 2:
The indicator mechanism is designed to automatically indicate wire insertion status without requiring external power or complex electronics. The mechanical flag moves or changes appearance based on the physical state of wire insertion, providing self-service indication that is both simple to manufacture and clear to observe.
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
Ensures proper wire insertion without enlarging the circuit breaker's size, offering a visual indication to prevent arcing and thermal issues, enhancing installation reliability.
Implementation Method 1
a return spring located below a lug and beyond the pivot such that the return spring is located 'indirectly' behind the lug
Data Source
AI summary
A residential circuit breaker is provided with a mechanism for showing proper installation of a wire to ensure that an installer/a contractor is aware that the wire has been fully inserted into a lug. The residential circuit breaker comprises a lug wire indicator, comprising: an indicator flag with an extension that is extended beyond a pivot of the indicator flag, and a return spring located below a lug and beyond the pivot such that the return spring is located “indirectly” behind the lug, and wherein the lug wire indicator provides a visual indication that a wire is inserted all the way into the lug before tightening a pressure screw.