Texas Electrician ExamTexas journeyman & master

The rule that fails more real installations than any calculation

It is short, it is easy, and it is the most common reason a panel gets red-tagged. It is also reliable exam material for exactly that reason.

On this page
  1. Three dimensions, and the one people forget
  2. Why depth depends on what is behind you
  3. The storage rule people ignore
  4. Illumination and entry
  5. What this page cites

Three dimensions, and the one people forget

The working space in front of electrical equipment is a three dimensional box, not a floor marking A panel is mounted on a wall. In front of it a rectangular volume is marked out and you stand inside it. Depth runs from the live parts out to the surface behind you, and how much depth is required depends on the voltage and on what that surface is. Width is the greater of thirty inches or the width of the equipment, measured across the equipment. Height runs from the floor to six and a half feet or the top of the equipment, whichever is higher. The whole volume stays clear, and it is not storage. panel KEEP CLEAR not storage, floor to 6½ ft you, facing the panel height floor depth measured from the live parts, not from the enclosure door WIDTH 30 in, or the equipment if it is wider. measured across the face, so it does not appear on a side view like this. HEIGHT 6½ ft from the floor, or the top of the equipment if that is higher. DEPTH, and what decides it the surface behind you. concrete is a grounded surface, a stud wall is not, and the worst case needs more room. all three apply at once. failing any one is a violation.
Depth, width and height are three separate rules. Most people only remember the depth one. Drawn against NEC 110.26(A)(1) through (A)(3). Look the depth up in your book.

Working space is defined by depth, width and height, and all three have to be satisfied (NEC 110.26).

Depth varies with voltage and with what is on the other side of the space, which is the part that surprises people. Facing a grounded surface is different from facing an insulated wall, which is different from facing other live parts.

Width has a minimum and is measured relative to the equipment. Height is a clear space that cannot be used for storage.

Why depth depends on what is behind you

Because the risk being managed is you touching something energised while your back is against something that completes a circuit.

A concrete wall behind you is a grounded surface. A wooden stud wall is not. The code asks for more room in the first case because the consequence of a slip is worse.

Once you see that, the three conditions stop needing memorization.

The storage rule people ignore

The working space is not storage. The dedicated space above certain equipment is also not storage.

This is the single most cited violation on real jobs, because a clear space in an unfinished room does not stay clear once the building is occupied.

On the exam it appears as a question about whether a described installation complies, with the violation hidden in a sentence about what else is in the room.

Illumination and entry

There are requirements for illumination of working spaces, and for entrance to and egress from working space around larger equipment.

The egress rules scale with equipment size and voltage, and above certain thresholds a second entrance or specific door hardware comes into play.

These are short subsections and they are exactly the kind of detail an exam uses to separate people who read the section from people who know the general idea.

What this page cites

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Every rule here is cited to the section it comes from, and corrections are logged in public with the date. This is study material rather than electrical advice, and it does not replace your own code book or your inspector.