Hybrid Neutral Bus Bar Resolving Plug-on and Pigtail Interference
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Solution Overview
Problem
Existing hybrid neutral bus bars face difficulties in securely accommodating both plug-on neutral and pigtail-neutral circuit breakers due to design limitations, such as interference from tightening screws and challenges in securing neutral clips, leading to complex wiring and increased installation time.
Innovation Solution
A neutral bus bar with an elongated body featuring a recessed channel rail and wire connectors, allowing for both plug-on and wire connections without additional components, with shaped areas to enhance securement of neutral clips and positioning of tightening screws to prevent interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a flat top surface rail is used to accommodate both pigtail and plug-on circuit breakers, then the rail can support wire connections with tightening screws, but the tightening screws interfere with proper securement of neutral clips and make plug-on connections difficult
Solution Approach 1:
The rail is segmented into distinct functional zones: a first portion with a flat top surface for wire connections and tightening screws, and a second portion with a curved top surface for plug-on neutral clip connections. This segmentation allows each zone to be optimized for its specific function without interference from the other connection type.
Solution Approach 2:
Different portions of the rail have different surface geometries tailored to their specific functions. The first portion has a flat surface suitable for wire connections, while the second portion has a curved surface that facilitates proper engagement of neutral clips. This local differentiation resolves the interference problem between the two connection types.
2Strength
If tightening screws extend above the top surface of the rail, then wire connections can be secured, but the screws interfere with proper connection of the neutral clip onto the rail
Solution Approach 1:
The rail is divided into separate zones where wire connections and plug-on connections occur in different locations. The wire connection zone allows screws to extend above the surface, while the plug-on zone is positioned where screw interference does not occur, enabling both connection types to function properly simultaneously.
Solution Approach 2:
The problem is resolved by utilizing the longitudinal dimension of the rail to separate the two connection types into different zones. Rather than trying to accommodate both connections at the same location, the rail extends in length to provide separate areas optimized for each connection method.
3Ease of manufacture
If pigtails are used to connect circuit breakers to the neutral conductor, then connection is possible, but additional pigtails crowd the wiring gutter and make wiring more difficult as more breakers are added
Solution Approach 1:
The plug-on neutral connection technology extracts the neutral connection function from the wiring gutter area by providing a dedicated neutral bus bar with integrated connection points. This removes the need for pigtails to traverse through the crowded wiring gutter, simplifying the overall panel layout and reducing clutter.
4Reliability
If wire connections are used with tools required for tightening, then secure connections are achieved, but wiring becomes more time consuming
Solution Approach 1:
The plug-on neutral connection is designed as a self-servicing connection mechanism where the neutral clip automatically engages with the rail and secures itself through spring pressure or deformation, eliminating the need for external tightening tools and operations while maintaining reliable electrical contact.
Data Source
AI summary
A neutral bus bar for an electrical distribution apparatus. The neutral bus bar includes an elongated body that has a rail and a plurality of wire connectors arranged. Each of the wire connectors includes a side hole on the body and a top hole. The side hole can receive an electrical neutral wire such as from a pig tail type circuit breaker. The top hole has a mouth which opens onto the recessed channel and can receive a tightening screw to secure the received electrical wire in the side hole.