Backfeeding Photovoltaic Arrays Through Main Breaker Boxes
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Solution Overview
Problem
The existing systems for connecting photovoltaic arrays to main circuit breaker boxes face challenges such as bus bar overload due to backfeeding, which can damage the bus bars and violate electrical codes, and require costly upgrades or separate breaker boxes, with existing solutions being either costly or prone to accidental repositioning issues.
Innovation Solution
A system that connects the power input lines from photovoltaic arrays and utility sources directly into a single circuit breaker, allowing backfeeding without using the bus bars, using a supply-side line-tap approach with various connector designs to ensure electrical contact and safety, including nested screws and insulation piercing connectors, allowing for efficient backfeeding without upgrading the bus bars or installing new breaker boxes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If photovoltaic array power input lines are connected to bus bars through separate breakers, then power can be backfed to utility, but bus bars may be overloaded exceeding their amperage ratings
Solution Approach 1:
The patent combines the utility power input and photovoltaic array power input into a single circuit breaker housing. The breaker housing integrates both power sources and connects them to the bus bar through a single overcurrent device, eliminating the need for separate breakers and preventing bus bar overload by centralized current control.
Solution Approach 2:
The single circuit breaker housing serves multiple functions: it protects both utility and photovoltaic power inputs, controls current from both sources, and prevents overload on the bus bar. This multi-functional design replaces what would traditionally require separate protective devices for each power source.
2Object-affected harmful factors
If utility input breaker and solar input breaker are positioned at opposite ends of breaker box, then bus bar overload is prevented, but inadvertent repositioning could cause overload and the photovoltaic system breaker's maximum amperage is still limited
Solution Approach 1:
By merging both power inputs into a single breaker housing, the patent eliminates the positioning issue entirely. The integrated design ensures that utility and photovoltaic currents are always controlled together through a single overcurrent device, making repositioning irrelevant and preventing overload regardless of physical arrangement.
3Power
If entire breaker box is upgraded with higher amperage bus bars, then backfeeding capability is improved, but installation cost and time increase
Solution Approach 1:
The single circuit breaker housing provides universal protection and control for both utility and photovoltaic power sources, enabling high-capacity backfeeding without requiring upgraded bus bars. The integrated design allows the existing breaker box infrastructure to handle increased power capacity through intelligent current management rather than physical upgrades.
4Object-affected harmful factors
If separate secondary breaker box is installed for photovoltaic array, then bus bar overload is avoided, but installation cost and space requirements increase
Solution Approach 1:
The patent merges the photovoltaic power input protection and control into the main utility breaker housing, eliminating the need for a separate secondary breaker box. This integrated approach prevents bus bar overload while reducing system complexity, installation cost, and space requirements by consolidating protective devices.
Data Source
AI summary
A circuit breaker system is provided that receives combined power inputs from a utility and from an alternative energy source for backfeeding to the utility through a standard breaker box without overloading the bus bars of the breaker box.