What's the best spacing for shop-light fixtures?

I'm in the process of completing my new shop at home, and I have a load of fluorescent lights to install. How should I space them for best effect?
—Bob Crain, Spring Valley, N.Y.

Congratulations on your new shop, Bob. You need to create adequate illumination that overlaps to eliminate shadows or dark corners. Referring to the drawing, above, here are some simple rules for doing just that.

Start by measuring the height (A) from your work surfaces to the expected height of the light fixtures. Assuming you plan to install your fixtures in unbroken rows across the ceiling, the distance from the outermost fixture to the wall (B) should be about one half the distance of (A). The distance between fixtures (C) should be about 1–1¹⁄₂   times (A).

For example, a typical 24×24' shop with a 10' ceiling and 36"-high work surfaces gives you a distance of 7' for (A). Three 16' rows of lights (each consisting of two 8' fixtures or four 4' fixtures) spaced 8' apart (C) leaves 4' all around from fixture to wall (B).

Some shadows can't be avoided, so add task lighting where needed to take care of any workstations that are still in shadow.