NEC · 110.26

Working Space & Clearances (110.26)

Section 110.26 sets the floor for every electrical installation: a clear, accessible zone in front of panels and equipment that inspectors enforce on every job — and the exam tests the numbers.

NEC 2017 2020 2023 Last updated 2026-06-27

Why working space rules matter

Section 110.26 is not about the conductors or the breakers — it is about the space around them. The NEC requires a defined zone in front of electrical equipment so that electricians can work safely, operate disconnects quickly, and escape rapidly if something goes wrong. Without that space, even properly installed equipment becomes hazardous the moment someone has to work on it.

On the journeyman exam, 110.26 appears in scenario questions: a panel is installed in a closet, or a subpanel is mounted in a mechanical room with ductwork running in front of it. The question asks whether the installation complies. To answer correctly, you need to know three things — the required depth, the required width and height, and the rule that governs the space above the equipment. Getting even one of those wrong changes the answer.

Inspectors treat 110.26 as a near-automatic checklist item on every panel inspection. It is one of the most frequently cited NEC violations in the field, which is exactly why it shows up reliably on licensing exams.

Depth of working space (Table 110.26(A)(1))

The required depth of the clear working space in front of electrical equipment is set by Table 110.26(A)(1), and it varies based on two factors: the voltage to ground of the equipment, and the condition of the area on the opposite side of the working zone.

The table organizes situations into three conditions:

  • Condition 1: Exposed live parts are on one side only, and the opposite side has no live or grounded parts — for example, a panel mounted on a concrete wall with nothing exposed on the wall face.
  • Condition 2: Exposed live parts are on one side and grounded parts — such as grounded metal surfaces — are on the opposite side of the working space.
  • Condition 3: Exposed live parts are present on both sides of the working space — a situation more common in industrial installations with equipment on opposite walls.

At voltages up to 150 volts to ground, all three conditions require the same minimum depth, which is 3 feet. This covers most 120-volt and 208/120-volt residential and light-commercial panels. At higher voltages — in the range up to 600 volts — the required depth increases as the condition becomes more hazardous: Condition 2 calls for a greater depth than Condition 1, and Condition 3 requires the most depth of all.

For the journeyman exam at typical residential and commercial voltages, the 3-foot figure under Condition 1 is the most tested value. Know it cold, and know that the depth grows as voltage rises or as grounded or energized parts appear on the opposite side.

Width, height, and the clear-working-space box

In addition to depth, 110.26(A)(2) sets a minimum width for the working space: at least 30 inches, measured from the front of the equipment, or the full width of the equipment — whichever is greater. A 24-inch-wide panel in a 30-inch-wide alcove satisfies the width requirement. A 42-inch-wide switchboard needs at least 42 inches of clear width in front of it, because the equipment is wider than the 30-inch floor.

Section 110.26(A)(3) sets the minimum height of the working space at 6 feet 5 inches measured from the grade, floor, or platform, or the height of the equipment — whichever is greater. Tall equipment that exceeds 6 feet 5 inches defines its own required headroom. This minimum ensures that a person of average height can stand upright while working at the equipment.

Together, these three dimensions — depth, width, and height — define a rectangular zone that must be kept completely clear. The zone is not a storage area, not a pathway for other trades, and not a conduit highway.

Dedicated equipment space (110.26(E))

Section 110.26(E) adds a separate requirement that goes beyond the working space directly in front of the equipment. It reserves the column of space directly above (and, for indoor equipment, below) the equipment footprint exclusively for the electrical equipment and its associated wiring. This dedicated equipment space extends from the top of the equipment to the structural ceiling, or to a height limit specified in the Code — whichever is lower.

The purpose is to prevent foreign systems — plumbing pipes, HVAC ductwork, sprinkler mains — from running through the zone above the panel. A water pipe passing directly above a panel creates a maintenance hazard: a leak could drip directly onto energized equipment, and the pipe forces anyone servicing the panel to work around an obstruction in a space the Code reserved for the electrical trade.

For indoor equipment, 110.26(E)(1) is an absolute prohibition: the dedicated space above the panel — extending from the top of the equipment to 6 feet above the equipment or to the structural ceiling, whichever is lower — must be kept completely clear of all foreign systems. No piping, no ductwork, and no leak-protection apparatus (including drip pans) may be installed in that indoor zone. There is no drip-pan exception for indoor equipment; a drip pan does not bring a foreign system into compliance. Outdoor equipment is subject to the separate provisions of 110.26(E)(2), which address that different installation environment.

Requirement Section Key value / rule
Working space depth 110.26(A)(1) Varies by voltage and condition; 3 ft at 0–150 V (all conditions)
Working space width 110.26(A)(2) 30 in. or width of equipment, whichever is greater
Working space height 110.26(A)(3) 6 ft 5 in. or height of equipment, whichever is greater
Dedicated equipment space 110.26(E) Above (and below) the equipment footprint — electrical use only
Illumination 110.26(D) Working space must be illuminated for all indoor installations

Access to the working space is covered by 110.26(C): at least one entrance of sufficient size must provide access to the working space. For large equipment rooms — where the working space on one side exceeds 6 feet in depth — two access doors or entries may be required so that personnel have an escape route. Exam questions about switchgear rooms and large panelboard installations often hinge on this two-entrance requirement, which kicks in based on equipment width and the depth of the working space, not on a simple square-footage threshold.

The combination of working-space depth, clear width, required height, and dedicated overhead space makes Section 110.26 a self-contained checklist. On the exam, read the scenario carefully for voltage, what is on the opposite side of the working space, and whether anything is installed overhead or in the path of access — those are the variables that change the answer.

Practice questions on this rule

Real journeyman-exam practice questions from Loomi's bank — answer first, then reveal the explanation.

Q1 NEC 110.26(B)

Under 110.26(B), when is guarding of exposed live parts in the working space required?

  1. A Whenever any live parts are exposed, regardless of location
  2. B Only when the equipment is rated over 600 volts
  3. C Only during scheduled maintenance shutdowns
  4. D When normally enclosed live parts are exposed for inspection or servicing and the space is in a passageway or general open space
Show answer & explanation

Correct: D — When normally enclosed live parts are exposed for inspection or servicing and the space is in a passageway or general open space

110.26(B) ties guarding to a specific condition: normally enclosed live parts exposed for inspection or servicing, in working space located in a passageway or general open space. It doesn't apply to every exposed live part, isn't tied to a voltage threshold, and isn't limited to shutdowns.

Q2 NEC 110.26(E)

Which best describes the vertical boundary of the indoor dedicated electrical space above a panelboard?

  1. A It extends 1.8 m (6 ft) above the equipment regardless of ceiling height
  2. B It extends 3 m (10 ft) above the equipment to match typical working space height
  3. C It extends to the structural ceiling regardless of how high that ceiling is
  4. D It extends 1.8 m (6 ft) above the equipment or to the structural ceiling, whichever is lower
Show answer & explanation

Correct: D — It extends 1.8 m (6 ft) above the equipment or to the structural ceiling, whichever is lower

110.26(E)(1)(a) sets the boundary at 6 ft above the equipment or the structural ceiling, whichever is lower — a low ceiling caps the zone shorter than 6 ft, so neither 'regardless of ceiling height' option nor a flat 10 ft figure is correct.

Q3 NEC 110.26(C)

A 900-ampere switchgear lineup has a personnel door 20 ft from the nearest edge of its working space. What does 110.26(C)(3) require for that door?

  1. A It only needs panic hardware if the equipment is rated 1200 amperes or more
  2. B It must remain locked at all times whenever the equipment is energized
  3. C It must be at least 24 in. wide to match the entrance requirement in 110.26(C)(2)
  4. D It must open at least 90 degrees in the direction of egress and be equipped with listed panic or fire exit hardware
Show answer & explanation

Correct: D — It must open at least 90 degrees in the direction of egress and be equipped with listed panic or fire exit hardware

Per 110.26(C)(3), equipment rated 800 A or more with a personnel door less than 7.6 m (25 ft) from the nearest working space edge must have that door open at least 90 degrees toward egress with listed panic or fire exit hardware. The 24 in. width rule belongs to the entrance requirement in 110.26(C)(2), not personnel doors, and the 1200 A figure is the two-entrance threshold, not the door-hardware threshold — 800 A is what triggers 110.26(C)(3).

Q4 NEC 110.26(F)

A switchgear room is kept locked at all times, with keys held only by maintenance electricians. How does 110.26(F) classify this room?

  1. A Not accessible, since a key is required to enter
  2. B Accessible to qualified persons
  3. C Accessible only during scheduled maintenance windows
  4. D Accessible to qualified persons only if a warning sign is posted
Show answer & explanation

Correct: B — Accessible to qualified persons

110.26(F) states that locked electrical equipment rooms or enclosures are considered accessible to qualified persons — the lock doesn't change that classification, and no signage or time-window condition is imposed by this section.

All General Requirements practice questions (Article 110)

Frequently asked questions

What is the minimum depth of working space in front of a panel?
The required depth depends on the voltage to ground and the condition of the opposite side of the working space, as described in Table 110.26(A)(1). At voltages up to 150 volts to ground, a minimum of 3 feet is required under all three conditions. At higher voltages (up to 600 volts), the required depth increases under conditions where exposed live parts face grounded parts or other live parts on the opposite side. Always verify the depth against the voltage and condition in the adopted edition of the Code.
Can you store things in the working space in front of a panel?
No. The working space required by 110.26 must be kept clear at all times. Using it for storage — even temporarily — is a Code violation that inspectors enforce consistently. The space must be available for safe operation and maintenance of the equipment.
What is the dedicated equipment space above a panel, and why does it matter?
Section 110.26(E) reserves the space directly above (and below) electrical equipment — extending from the top of the equipment to the structural ceiling or to a specified height limit, whichever is lower — exclusively for electrical use. Plumbing pipes, HVAC ducts, and other non-electrical systems may not run through this zone. Inspectors commonly cite violations when mechanical trades install equipment overhead after the electrical rough-in is approved.
Related articles
Service Disconnecting Means (230.70) Service equipment must meet 110.26 clearances — location rules interact directly. Overcurrent Protection (Article 240) Panel boards and distribution equipment are the most common 110.26 inspection targets. Services (Article 230) Service entrance equipment must satisfy working-space requirements before the inspector approves rough-in. Service & Feeder Calculator Correctly sized equipment is easier to install with adequate working space planned from the start.
Loomi · NEC exam prep

Practice the NEC concepts in this article.

Loomi turns NEC content into 12,934 spaced-repetition exam questions built for the journeyman test. Try everything free for 3 days.

Get launch access