Up, across and down

How it's done on site

Conduit from a box in a wall usually goes up. It leaves through the top, runs in the space above the ceiling, and drops into the next box. That space is where the runs can be reached later; going under the floor means the slab, and usually somebody else's space.

What went wrong

The add-in took the shortest way out of each box, and on those boxes that was through the bottom. Every rule was kept: clear of obstacles, room for every elbow. It still dropped about 400 mm under the floor to get between two boxes on the same wall.

That's the harder kind of mistake. A route that fails is obvious. A route that works but isn't how anyone would build it has to be noticed, deleted and drawn again by hand.

Top first

Now a box is left through the top whenever it can be. If the top openings are taken or blocked, a side; the bottom only when nothing else will do. Boxes on the same wall are joined up, across and down.

Boxes are solid

A box is also something to keep clear of, except straight out of its openings. A route can't pass through one, or leave from its back. Each opening carries one run, and a box that already has a run gets the next through a free opening instead of failing.

Families vary

Box families differ from office to office. Some put several connectors on a single opening; many receptacle families have no conduit connector at all. Routes handle both: openings are never shared, and a device without a connector is still reached, with the end named in the preview so it can be joined by hand.

The test

Clear of obstacles is the minimum. The real test is whether an electrician would run it that way.