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?

You are wrong.
The integral device refered to in 300-15(E)is a self contained device such as a receptacle that clamps onto NM cable.
Article 314 covers outlet boxes.

I would never allow the oak box to be used alone. Why don't you install a box inside the oak box? You have indicated there is plenty of room.

Earl

I may use a round old-work box as you suggested. What was holding back was-
1. This is a new custom built oak piece that cost a couple thousand bucks. Mistake = hari kari.

2. Cutting the hole for the box and avoiding cutting the wires is going to be a challenge. I will use a hand-saw and go slowly.

A 4 1/8" hole saw would be fine for a typical metal old work round box.

This is a good idea it solves the depth problem. I can mark on the hole saw how deep I want to go with a sharpie.

Also makes a nicely shaped hole. Does Oak splinter like crazy? Maybe I should put some masking tape down.


Thanks
Eric

Well it could , I would do the tape trick and I suggest running the saw in reverse just enough to scribe a full circle.

Then carefully forward.

How about a pancake box? So long as you have a canopy, there will be room for the splices, maybe you won't have to cut the headboard?

Earl