300-15 deals with where boxes are required.
Part e. states that an integral listed enclosure is permitted.
The job I'm on has a built-in custom bookcase with an enclosed oak box occupying the center of one of the shelves. A surface mount light has been mounted to the face of this box. The wires are capped inside the canopy.
I feel that the volume of the canopy is too small and that 300-15e would allow me to terminate the connections inside the 'integral' supported oak box. The splices would have more than adequate volume and protection, as well as support for the light fixture. However, since it is a custom piece, it is not listed.
Am I right?
Is there another article that better covers this?