19.1 Working Space & Dedicated Equipment Space (110.26)

Why 110.26 Owns the Safety Outline Slice

Prov’s Arkansas Journeyman outline reserves Safety for 3 scored items on the 60-question, 3-hour, 70% cut-score NEC 2023 form. Those three stems will not always say “Safety” out loud — they often look like a panel layout, a water heater shoved in front of a disconnect, or a duct running through the space above a switchboard. The Code home for that pattern is 110.26.

Chapter 6 already touched working space beside service equipment. This section is the Safety deep dive: Conditions, the full depth table logic, width vs depth vs headroom, illumination, large-equipment entrances, and dedicated equipment space so you do not confuse two different “clearance” ideas under time pressure.

Tab 110.26, Table 110.26(A)(1), 110.26(C), 110.26(D), and 110.26(E) permanently. Pair them mentally with 110.27 (guarding) when a stem mixes live-part exposure with aisle space.

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Scope — What Triggers Working Space?

110.26 applies about electrical equipment that is likely to require examination, adjustment, servicing, or maintenance while energized. Panelboards, switchboards, switchgear, motor control centers, and many disconnects qualify. The working space exists so a worker can operate and maintain the equipment safely — it is not storage for paint, lumber, refrigerators, or water heaters.

If a stem describes cardboard, ladders, or HVAC equipment parked in front of a panel, the Code problem is access/working space under 110.26, not ampacity under Article 310.

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Depth — Table 110.26(A)(1) Workflow

110.26(A)(1) sends you to Table 110.26(A)(1). Depth is not a single memorized number. It depends on:

1. Nominal voltage to ground (not always line-to-line), and
2. Condition 1, 2, or 3 — what sits opposite the live parts across the working space.

Conditions (paraphrased — confirm Exact Code text)

Exam skill: convert the stem into a Condition first. “Open panel across from a brick wall” is Condition 2 thinking. “Two open panelboards facing each other across an aisle” is Condition 3. “Live parts on one side, open space / insulated opposite side” is Condition 1.

High-yield table cells (verify in your NEC 2023)

Trap that fails candidates: assuming Condition 2/3 always deepen the 0–150 V row. On the 0–150 V row, all three Conditions are 3 ft. The classic 3½ ft / 4 ft increases show up on the 151–600 V row (for example, many 480Y/277 V systems where voltage to ground is 277 V).

Workflow under the clock:

1. Identify volts to ground from the system described.
2. Classify Condition 1 / 2 / 3 from what faces the worker.
3. Open Table 110.26(A)(1) and read that cell only.
4. Do not answer a depth question with the 30-inch width rule.

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Width — 110.26(A)(2)

The width of the working space in front of the electrical equipment shall be the width of the equipment or 30 inches, whichever is greater. In all cases, the working space shall permit at least a 90-degree opening of equipment doors or hinged panels.

Depth (table feet) and width (inches / equipment width) are different measurements. A stem that asks “how wide” wants 110.26(A)(2); a stem that asks “how deep / clear distance in front” wants the table.

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Headroom — 110.26(A)(3)

The height of the working space shall be clear and extend from the grade, floor, or platform to a height of 6½ feet (6 ft 6 in) or the height of the equipment, whichever is greater. Limited exceptions exist (including certain existing dwelling service equipment / panelboards not exceeding 200 A) — open the exception only when the stem screams “existing dwelling” and small ampacity.

Do not mix numbers: working-space headroom 6½ ft is not the same as dedicated equipment space “6 ft above the equipment” in 110.26(E).

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Entrance to Working Space — 110.26(C)

For equipment rated 1200 A or more and over 6 ft wide, 110.26(C)(2) requires entrance to and egress from the working space by at least two means (doors at each end or the Code’s permitted alternatives). Smaller dwelling panels almost never hit this trigger; commercial switchboards often do.

110.26(C)(3) addresses personnel doors in the egress path for large equipment — including direction of door swing and listed panic hardware under the section’s conditions when the door is within 25 ft of the working-space edge. If the stem piles 1200 A + width over 6 ft + door hardware, open 110.26(C) before inventing an Article 230 answer.

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Illumination — 110.26(D)

110.26(D) requires illumination for working spaces about service equipment, switchboards, switchgear, panelboards, or motor control centers installed indoors. Additional rules limit how automatic controls may leave a worker in darkness while standing in the working space. For Prov Safety items, remember: indoor working spaces about that equipment need lighting, and the lighting arrangement must not defeat safe work in the clear space.

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Dedicated Equipment Space — 110.26(E)

Working space protects the person in front. Dedicated equipment space protects the equipment’s installation zone — especially above — so wiring can enter and foreign systems do not occupy the reserved volume.

For indoor installations, 110.26(E)(1) generally requires dedicated space equal to the width and depth of the equipment, extending from the floor to 6 ft above the equipment or to the structural ceiling, whichever is lower. Piping, ducts, leak sources, and other foreign systems are restricted in that zone unless the section’s protection/foreign-system permissions are met. Outdoor equipment has related dedicated-space rules in 110.26(E)(2).

A stem can violate both: storage in the aisle (A) and a sprinkler main through the zone above (E). Answer the asked piece.

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Guarding Crossover — 110.27

When live parts are exposed, 110.27 guarding/enclosing rules travel with working-space questions. Safety stems sometimes ask whether parts must be enclosed, guarded by location, or protected by locked rooms rather than asking for table depth. If the stem is about who can reach live parts, start at 110.27; if it is about where a worker stands, stay in 110.26.

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Arkansas Prov Drill Pattern

With only 3 Safety items, expect high-yield classics:

1. Depth from Table 110.26(A)(1) after Condition + volts-to-ground classification
2. Width 30 in vs equipment width
3. Headroom 6½ ft
4. Storage in working space = violation
5. Dedicated space above ≠ front working space
6. Large-equipment dual entrance when 1200 A and over 6 ft wide

Open-book pacing: find 110.26 in under 20 seconds, classify Condition in under 30 seconds, read one table cell, move on.

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Timed Open-Book Tips for §19.1

• Permanent-tab Table 110.26(A)(1) and highlight the 0–150 and 151–600 rows.
• Always convert line-to-line stems into volts to ground before opening the table.
• Width answers are usually 30 inches; depth answers are usually 3 / 3½ / 4 / 5 feet depending on row and Condition — do not swap units.
• Remember: on 0–150 V, Conditions 1–3 are all 3 ft — do not invent a deeper number from the 151–600 V row.