A blank electrical-box cover was included in my wiring-supply purchases.
The featured Amazon option is Sigma 14240 Blank Outlet-Box Cover.
Where it fits my build
I brought the roof light wires and camera cables into a PVC conduit layout. That work included drilled enclosures, threaded fittings, cable glands, solder-seal splices and grouped wiring.
During the small-box stage, I drilled for a male PVC fitting and used a fitting inside as a retaining nut. I routed the camera cable through a gland into a tee and brought the light-wire groups toward the van entry.
The larger roof enclosure during my cable-entry work.A grouped roof-wire connection before the final conduit work.
My build notes
The wiring project was a sequence of individual connections and routes. The photographs show the intermediate stages, including open boxes and wrapped wire groups, before the remaining covers and conduit joints were finished.
I built the cable route a section at a time, bringing local connections into the larger conduit system.
Alternative products
Two alternatives to compare
The featured blank cover closes an unused box face. The indoor blank wall plates and projecting in-use cover address different box-face arrangements, rather than one shared enclosure shape.
ENERLITES White Blank Wall Plates
These white blank plates cover unused single-gang wall-box openings. The ten-pack has a plain face without an outlet or cable opening.