Modular Panelboard with Compartmentalized Circuit Breakers
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Solution Overview
Problem
Existing electrical panelboards pose a risk of exposure to live parts and arcing incidents during the installation or removal of circuit breakers, particularly in load centers, where deenergization is inconvenient and may not be feasible, especially in critical applications like data centers and hospitals.
Innovation Solution
A modular panelboard design with compartmentalized circuit breaker units, nonconductive backplanes, and pin-shaped stabs covered by shutter plates, along with removable caps for wiring gutters, which reduces the chance of contact with live conductors and arcing events by keeping all terminal connections internal and using positive retention interlocks to prevent insertion or removal in the ON position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If circuit breakers are mounted directly to the panelboard for easy access and installation, then ease of operation is improved, but the risk of exposure to live parts and arcing incidents increases
Solution Approach 1:
The panelboard is divided into separate compartments, each housing an individual circuit breaker. These compartments are isolated from each other by nonconductive barriers, allowing operators to access and operate one circuit breaker without exposing themselves to other live parts in the panelboard.
Solution Approach 2:
Nonconductive shutter plates and insulating barriers are introduced as intermediary elements between the circuit breakers and operators. These intermediaries physically separate the operator from live conductors while still allowing operational access to the circuit breakers through designed access points.
2Reliability
If power is shut off to the panelboard to prevent contact with live conductors, then safety is improved, but availability and operational continuity deteriorates
Solution Approach 1:
By compartmentalizing the panelboard into isolated sections, the system allows selective deenergization of individual compartments rather than requiring complete shutdown. This enables maintenance work on one circuit breaker while other compartments remain energized and operational.
Solution Approach 2:
Interlock mechanisms are pre-configured to automatically detect when a circuit breaker is in the ON position and prevent its removal from the compartment. This preliminary safety action ensures that operators cannot accidentally expose themselves to live parts while attempting to install or remove breakers, eliminating the need for complete power shutdown.
3Ease of operation
If circuit breaker compartments are open for easy access, then ease of operation is improved, but the risk of arcing incidents increases
Solution Approach 1:
The harmful factor of arcing is extracted and contained within isolated compartments. Each compartment is designed to confine any potential arc to a small, enclosed space surrounded by nonconductive materials, preventing the arc from propagating to other circuit breakers or components in the panelboard.
Solution Approach 2:
Nonconductive shutter plates and insulating barriers serve as intermediaries that physically separate circuit breakers from each other and from the panelboard housing. These intermediaries prevent arc propagation by blocking the path between live parts, while still allowing operational access when properly designed.
4Reliability
If comprehensive covering panels are installed over all circuit breaker faces, then safety is improved, but ease of operation and accessibility deteriorates
Solution Approach 1:
Instead of a single comprehensive cover, the panelboard uses segmented compartmentalized structures with individual access points for each circuit breaker. Each compartment can be accessed independently through its own shutter or opening, providing protection when not in use while maintaining ease of operation when needed.
Solution Approach 2:
Fixed comprehensive covering panels are replaced with dynamic shutter mechanisms that can be opened and closed as needed. These shutters provide full protection when closed but can be quickly opened to allow operator access to circuit breakers, and then closed again to restore protection, adapting to the operational state of the panelboard.
Data Source
AI summary
A panelboard is composed of modular units. Each unit has compartments for circuit breakers, side walls, and wiring gutters. A main circuit breaker unit has a main cable compartment having separate compartmentalized routing for power cables, and a compartment for the main breaker. A branch circuit breaker unit is edge connected to the main breaker unit. More branch breaker units may be added. Each branch breaker unit has a bus plane for line power, with pin-shaped stabs extending perpendicularly from its busses. The bus plane is covered by circuit breaker compartments in front and an insulative backplane in back. Branch wiring exit slots in the circuit breaker compartments lead to wiring gutters. Each unit is shaped and dimensioned to be mechanically and electrically connected together to form the whole panelboard. Caps for the wiring gutters are front accessible and constitute a front surface of the finished panelboard.