Electrical Box Cable-Port Sealing for Fire-Rated Mounting
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Solution Overview
Problem
Conventional electrical boxes made of plastic lack sufficient fire resistance and allow smoke to enter through large cable entry ports, failing to meet fire rating certifications.
Innovation Solution
An electrical box designed with a combination of injection moldable thermoplastic materials, featuring cable-clamping closure structures, sealing structures made from a pierceable rubber elastic material, and modular mounting systems, allowing for increased fire resistance and adaptability to various applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional plastic electrical boxes are used with large cable entry ports, then ease of cable installation is improved, but fire resistance rating deteriorates due to smoke entry through ports
Solution Approach 1:
A flexible grommet is provided within the cable entry port that can be deformed during cable installation to allow easy cable passage, then returns to its original shape to seal the port. This flexible membrane structure enables both easy cable installation and fire resistance by preventing smoke entry through the sealed port.
Solution Approach 2:
The grommet material undergoes parameter changes based on applied force - it becomes more compliant during cable installation to facilitate easy passage, then maintains its sealing properties under fire conditions to prevent smoke entry, effectively changing its mechanical properties based on operational state.
2Ease of manufacture
If a single standardized electrical box design is used, then manufacturing cost and complexity are reduced, but adaptability to different mounting applications deteriorates
Solution Approach 1:
The electrical box is designed with multiple types of mounting features integrated into a single standardized structure, including nail guides for direct stud mounting, bracket receiving slots for alternative mounting methods, and support structures for various installation scenarios. This universal design allows one box type to serve multiple mounting applications.
Solution Approach 2:
The mounting system is segmented into separate functional elements (nail guides, bracket slots, support structures) that can be selectively engaged depending on the application, allowing the single box design to adapt to different mounting requirements without requiring multiple box variants.
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 electrical box achieves enhanced fire resistance by preventing smoke entry through sealed cable ports and allows for versatile mounting options using interchangeable accessories, thus meeting various fire rating certifications and application needs.
Implementation Method 1
The second injection moldable thermoplastic material may be a pierceable material which closes off the aperture of the respective port while a cable or a cable channel may be pushed through the second injection moldable thermoplastic material such that the second injection moldable thermoplastic material sealingly encloses the cable or cable channel
Data Source
AI summary
The present disclosure generally relates to an electrical box, an assembly including such a box and a method for producing same. The electrical box may have a rear wall and opposing side walls made from an injection moldable thermoplastic material, wherein the side walls define a front opening opposite the rear wall. The electrical box may further have at least one cable entry port formed in one of the side walls wherein the at least one cable entry port is provided with at least one cable-clamping closure structure. Still further, the electrical box may have a slot structure comprising at least two retaining slots provided on opposed side walls each formed for receiving and retaining at least one nail guide or mounting bracket, and/or at least two support structures provided on opposed side walls at the front edge thereof wherein each support structure can have at least one round aperture for receiving a cylindrical shaft.