Circuit Interrupter Ground Voltage Detection
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Solution Overview
Problem
Existing Ground Fault Circuit Interrupters (GFCI) do not effectively trip when the grounding conductor is connected to a voltage source, potentially leading to user shock due to mis-wiring errors, as they are designed to never interrupt the grounding wire.
Innovation Solution
A circuit interrupter with a sensing circuit and control circuit that detects voltage on the grounding path and breaks the connection between input and output conductors, incorporating a switch and optional reset lockout assembly to prevent re-establishment of electrical continuity in case of mis-wiring or non-operational conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the GFCI is designed to never interrupt the grounding wire, then the grounding function is maintained, but safety is compromised when the ground conductor is mis-wired to a voltage source
Solution Approach 1:
The patent applies preliminary action by detecting voltage on the ground conductor before a shock hazard can occur. The sensing circuit continuously monitors the ground conductor for voltage presence, and if voltage is detected (indicating mis-wiring), the trip mechanism preemptively opens the hot and neutral conductors to prevent user shock. This proactive detection and prevention approach resolves the contradiction by maintaining grounding function while adding safety protection against mis-wiring scenarios.
2Object-affected harmful factors
If a sensing circuit is added to detect voltage on the ground conductor, then safety is improved, but device complexity increases
Solution Approach 1:
The patent applies universality by designing the sensing circuit to serve multiple functions: it detects voltage on the ground conductor, determines the presence of mis-wiring conditions, and triggers the trip mechanism. The control circuit integrates multiple detection capabilities (ground conductor voltage sensing, hot/neutral conductor monitoring) into a unified system that manages the trip mechanism. This multi-functional approach improves safety while minimizing the increase in device complexity by consolidating functions rather than adding separate independent systems.
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 safe operation by tripping the GFCI when a hot ground condition is detected, preventing user shock and ensuring proper wiring, even in cases of mis-wiring or open neutral conditions, thereby enhancing electrical safety.
Implementation Method 1
a sensing circuit coupled to a control circuit which, in turn, is coupled to the switch. The sensing circuit causes the control circuit to open the switch when there is a voltage on the grounding path that is not at the grounding potential.
Data Source
AI summary
A ground detector circuit in the form of a live ground detector circuit. This live ground detector circuit can be combined with a circuit interrupting device. The circuit interrupting device can have a grounding conductive path, and a set of contacts which are configured to break an electrical connection between input and output terminals on the circuit interrupting device when operated. The ground detector when combined with a circuit interrupter, triggers the circuit interrupter into a fault condition when the detector circuit detects the presence of a signal or a fault.