Transition Fitting for PV Cable Sealing in EMT
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Solution Overview
Problem
Conventional methods for routing photovoltaic cables into electrical metal tubing (EMT) often result in open exposure to rain or ineffective sealing when using electrical sealants, which can lead to unsightly connections and improper sealing if not installed correctly.
Innovation Solution
A transition fitting comprising a fitting body, grommet, nut with a ground lug, and compression fitting that creates a rain-tight seal by compressing the grommet around the cables, eliminating the need for separate sealants, with the grommet's bores sealing unused spaces and the nut's threads securing the EMT connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrical sealant materials are used to seal the entry of PV cables into EMT, then a seal between PV cables and EMT can be achieved, but the connection becomes unsightly and installation complexity increases due to improper sealing requirements
Solution Approach 1:
A transition fitting serves as an intermediary component between PV cables and EMT conduit. The fitting includes a body with a cable entry port and a conduit connection port, eliminating the need for sealants by providing a mechanical interface that inherently seals the connection through its structure and compression mechanism
Solution Approach 2:
The patent replaces the chemical sealing method (electrical sealant) with a mechanical sealing system. The transition fitting uses a compression mechanism where a clamp or compression element applies force to seal the cable entry port, providing a reliable seal through mechanical means rather than chemical adhesion
2Reliability
If a transition fitting with compression mechanism is used to create rain-tight seal, then sealing reliability is improved, but the device complexity and number of components increases
Solution Approach 1:
The transition fitting merges multiple functions into a single integrated component: cable support, sealing, conduit connection, and grounding. The fitting body incorporates a cable entry port with integrated grommet, external threads for conduit attachment, and a grounding provision, eliminating the need for separate sealants and mounting hardware
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 provides a reliable, rain-tight connection between photovoltaic cables and EMT without the use of electrical sealants, ensuring effective protection from rain and UV light while maintaining a clean and secure installation.
Implementation Method 1
the nut tightened upon the fitting body thereby compressing the grommet and forming a rain-tight fit around each of the PV cables
Implementation Method 2
External facets on the trailing end of the grommet mate with internal facets in the bore of the fitting body, thereby enabling the trailing end of the grommet to lock into the bore of the fitting body
Data Source
AI summary
A transition fitting for achieving a rain-tight transition at the entry of photovoltaic cables with EMT. The transition fitting includes a fitting body with an internal bore, a grommet seated within the bore, a nut for tightening the grommet against the fitting body, a compression fitting and a ground lug extending from the nut. A plurality of bores extend partially through the grommet. Photovoltaic (PV) cables may be inserted within one or more of the bores in the grommet and the nut tightened upon the fitting body to form a rain-tight fit around the PV cables. The skins of the grommet remain intact in any unused bores to maintain a rain-tight seal on any unused bores. The transition fitting will maintain a rain-tight seal at the entry of PV cables to EMT. The ground lug provides a means of grounding the EMT to the transition fitting.