Staff at Rapid City assembled the modular enclosures on site.
The application called for the equivalent of a 48" wide by 108" long by 36" deep junction box with openings on the top that fit against the ceiling. These openings would accept the cables running through the bore holes from motor control center above. The goal was to offer access for pulling and connecting cable and terminating numerous conduits in an enclosure that was corrosion resistant and light enough to hang from the ceiling.
Weller envisioned an upside down box with large rectangular holes in the bottom and a flat lid sealed by a gasket against the box. But hanging an enclosure of that size in the water plant basement posed problems due to a congested work area, with the added difficulty of hanging it upside down.
Midwest Plastic Fabricators (MPF) was selected to provide a custom-designed enclosure. MPF uses CNC technology and PVC material to manufacture enclosures, cabinets, and boxes for conduit and control systems.
Trading design concepts and ideas with the Ohio-based manufacturer, Weller's solution was a design/build project consisting of three separate enclosures that would assemble on site. Recognizing easy installation as a priority, MPF assembled the components prior to shipment to insure fit. The unit was then disassembled and shipped by motor freight as three separate enclosures.
Staff at Rapid City were able to attach the components to the ceiling, then to each other. The ease of cutting conduit entrances in the PVC assembly when in place made the many conduit connections and cable pulling a relatively simple task.
In another recent project, the Immokolee Wastewater Treatment Plant east of Naples, FL, used 20" x 18" x 8" PVC junction boxes as a water tight liner in traffic-rated concrete handholes. The junction boxes provide access for wire pulling and connection for the underground conduit system to remote service equipment. The PVC boxes featured a gasketed shoebox-style lid attached with stainless steel fasteners.
