An actual electricalbox, with concrete body, made by hand, based and photographed on a real one. Photo-real, high definition textures (around 6000 px).

Process:
Photos of the object; adjusting the textures of front, top and sides to make them vertically and horizontally aligned; erase unwanted details and shadows; import inside Blender (Image As Plane); modeling, adjusting the mesh and UV maps.

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Mainly worked for Cycle render.

The shader's nodes let you tweak all textures via Color Ramps: