The entire bookshelf unit in my living room was made by my husband. It has twelve enclosures total in two columns with six shelves on each side. The top four shelves on each column are fully enclosed with wood. The bottom two shelves have no wood backing. There is an outlet behind the bottom right shelf, which is where everything is plugged in.

To give me a way to route the transformers and cords through, he drilled a three-inch circle in the back bottom rear corner of the middle vertical wood piece between each pair of shelves. He then drilled a three-inch circular hole in the back bottom rear area of every horizontal shelf on the right column.

Put another way, imagine the three shelves on the left side of the bookcase. All the cords run to the right and pass through the side wall of the shelf, then travel down to the power strip through the bottom of each shelf on the right-hand side.

Because the cords are only so long, the power strip sits on one of the middle shelves. Even though the cords feed through the shelves neatly and the slack is held with rubber bands, all those cords and transformers still create a rather unsightly tangle. The shelf holding the power strip has hardback books lined up to the right. I took one of the hardbacks and set it facing forward in front of the power strip. It may look like I'm showcasing a book on the Middle Ages, but I'm actually using that book to hide the electrical clutter on that shelf.