Written against the 2026 NEC and checked section by section, September 2026
Working Space Practice Questions
Depth, width and height are three separate requirements and an installation satisfies all three or it fails, and none of them is the zone above the gear, which is a different subsection with different logic. These 25 items work the depth table by condition and voltage, the two dimensions nobody looks up, the two ampere thresholds that govern entrances and doors, the illumination rule with no number in it, and the dedicated space that people go looking for and cannot find.
Pick an answer and the explanation opens with the section it comes from. These are original questions written for this site, not questions from the exam. Have your own code book open: the Texas exam is open book, and looking the section up is the skill being tested.
Read the working space study page first if the topic is new to you.
1. What does the parent rule on spaces about electrical equipment call for?
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A. Working space, plus a way in and a way out of it, kept around every piece of electrical equipment so the gear can be operated and maintained readily and safely
Two words in it do the work later on. Maintained means the space has to still be there next year, which is what turns a storage question into a code question. Access and egress is a separate obligation from the dimensions, and it is what the entrance and personnel door subsections are about further down the section.
NEC 2026 110.26
2. The dimensions in the working space subsection attach to which equipment?
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B. Equipment likely to require examination, adjustment, servicing or maintenance while energized
That qualifier does real work, and a stem that describes the equipment carefully is often telling you whether the dimensions apply at all before it asks you for one. It is also why a junction box on a wall and a panelboard on the same wall are not the same problem. Once the qualifier is met, depth, width and height all apply together.
NEC 2026 110.26(A)
3. Where the live parts are enclosed, the depth of working space is measured from what?
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C. The enclosure front or the opening
On a dead-front panelboard that means the front of the can and not the bus behind it, and getting it backwards costs you the whole depth of the enclosure. Where live parts are exposed the measurement runs from the live parts instead, so the datum moves with the equipment and the stem has to tell you which case you are in.
NEC 2026 110.26(A)(1)
4. What describes Condition 2 in the depth table?
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D. Exposed or enclosed live parts on one side and grounded parts on the other, with concrete, brick or tile walls counted as grounded
The conditions are prose and not arithmetic, and they are decided by what sits on the other side of the space rather than by the equipment itself. The masonry sentence is the one that turns an ordinary mechanical room into Condition 2, since a concrete or block wall behind you is a grounded surface. A stud wall is not.
NEC 2026 Table 110.26(A)(1)
5. Live parts sit on both sides of a working space. What can still put the installation in Condition 1?
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A. Effective guarding of the live parts by insulating material
Live parts on both sides is not automatically Condition 3, and the guarding clause inside Condition 1 is the reason. An item that mentions an insulating barrier is testing precisely that, and reading past it costs you a foot or two of required depth in the 151 to 600 volt row. Read the guarding clause twice before you enter the table.
NEC 2026 Table 110.26(A)(1)
6. What does the illumination subsection prohibit inside the working space?
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B. Control of all the luminaires by automatic means
An occupancy sensor as the only control fails and a wall switch you can reach passes, because the point is that the lights cannot go out while somebody has their hands inside energized gear. No dimension is attached to this subsection at all, which is exactly why it gets asked. It applies to indoor installations of service equipment, switchboards, switchgear, enclosed panelboards and motor control centers.
NEC 2026 110.26(D)
7. An electrical equipment room is kept locked. How does the code treat it?
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C. As accessible to qualified persons
One short subsection, and it means a stem that mentions a locked electrical room is usually not describing a violation. Locking the room is a way of restricting access to qualified persons rather than a way of failing an accessibility requirement. Warning signs belong to the guarding of live parts in the next section and are a separate obligation.
NEC 2026 110.26(F)
8. What volume does the dedicated equipment space occupy indoors?
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D. The width and depth of the equipment, from the floor to 6 feet above the equipment or to the structural ceiling, whichever is lower
Working space is in front of the equipment and exists so a person can stand there. Dedicated space is the column the gear sits in and exists so somebody else's pipe does not end up over your equipment. Piping, ducts, leak protection apparatus and other equipment foreign to the electrical installation may not occupy that zone, and confusing the two spaces is the most productive mistake on this subject.
NEC 2026 110.26(E)
9. Two motor control centers on a 480Y/277 volt system face each other across an aisle, with exposed live parts on both sides and nothing guarding them. What clear depth does the table call for?
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A. 4 feet
Nominal voltage to ground on that system is 277, which puts you in the 151 to 600 volt row, and live parts on both sides with no guarding is Condition 3. The row gives 3 feet, 3 feet 6 inches and 4 feet across the three conditions, so this one is 4 feet. The 5 foot figure belongs to Condition 3 in the row above 600 volts.
NEC 2026 Table 110.26(A)(1)
10. A 120/240 volt panelboard has exposed live parts on both sides of the working space with no guarding. What is the minimum clear depth?
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B. 3 feet
The bottom row of the table gives the same 3 feet in all three conditions, so on a system at 150 volts to ground or less the condition never changes the answer. Knowing that saves you the argument about what is behind you on most dwelling and small commercial items, and it is worth confirming in your own copy so you trust it under a clock.
NEC 2026 Table 110.26(A)(1)
Ten down. If you want these timed and scored by content area, the practice exam runs thirty questions free, and the full bank of 178 plus the calculation ladder is $79 once.
11. Equipment operates at 800 volts to ground with exposed live parts on both sides of the working space and no guarding. What is the minimum clear depth?
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C. 5 feet
The top row of the table covers 601 through 1000 volts ac and 601 through 1500 volts dc, and it runs 3 feet, 4 feet, 5 feet across the conditions. Notice that Condition 1 is 3 feet in every row of the table, so the voltage only starts to matter once something live or grounded is on the other side of the space.
NEC 2026 Table 110.26(A)(1)
12. A dead-front switchboard has all connections and all renewable and adjustable parts accessible from the front. What does the section say about the back and sides?
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D. Working space is not required there, but 30 inches of horizontal space is required where rear access is needed to work on nonelectrical parts
The allowance and its condition sit in the same paragraph, and the condition is what an item is built on. Everything electrical has to be reachable from somewhere other than the back or sides before the allowance applies. The 30 inch figure is a smaller and different requirement that turns up only where somebody has to get behind the gear for nonelectrical reasons.
NEC 2026 110.26(A)(1)
13. Equipment in an existing building is being replaced, with dead-front assemblies across an aisle from each other. What does the section permit?
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A. Condition 2 clearance, where written procedures prohibit both sides being open at the same time and qualified authorized persons service the installation
This is a permission most people have never read, and it comes with two conditions that have to hold together: an adopted written procedure and qualified authorized persons doing the work. Neither is a physical measurement, which is what makes it easy to drop from an answer. It applies to existing buildings where equipment is being replaced, not to new construction.
NEC 2026 110.26(A)(1)
14. A personnel door serves the working space around a 1000 ampere switchboard containing overcurrent devices, 20 feet from the nearest edge of that space. What is required of the door?
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B. It swings a full 90 degrees the way a person leaves, and carries listed panic hardware or listed fire exit hardware
The door rule triggers at 800 amperes and at a distance under 25 feet, so both figures in this stem are inside it. The 1200 ampere figure governs how many ways out of the space there are and tells you nothing about how the door behaves. Two thresholds, two subjects, and items on this subject routinely hand you the wrong one to see whether you notice.
NEC 2026 110.26(C)
15. Six 400 ampere service disconnects stand side by side in a group measuring 7 feet across. Does the large equipment entrance rule reach them?
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C. Yes, because the combined rating is 1200 amperes or more and the combined width is over 6 feet
That second limb of the rule is the trap, because every piece of the lineup looks small on its own. Rating and width are both added across the group, and the group here reaches 2400 amperes across 7 feet. The other limb needs a single piece of equipment rated 1200 amperes or more that is also over 6 feet wide, and both halves of that one have to be true.
NEC 2026 110.26(C)(2)
16. What brings a large equipment installation back to a single entrance to the working space?
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D. Unobstructed egress, or working space depth twice that required by the depth subsection
Two exceptions, and only two. The extra depth version also fixes where the single entrance goes: the entrance has to sit at least the table clear distance away from the gear, read for that voltage and that condition. The unobstructed egress version turns on the location permitting a continuous and unobstructed way of egress travel.
NEC 2026 110.26(C)(2)
17. Where an entrance at each end of the working space is required, what size does each one have to be?
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A. Not less than 24 inches wide and 6-1/2 feet high
The 24 inch figure is easy to confuse with the 30 inch width of the working space itself, which is a different measurement in a different direction. The height matches the working space height, which keeps the whole path consistent. The same pair of figures turns up in the parent rule about equipment doors restricting access.
NEC 2026 110.26(C)(2)
18. When do open equipment doors count as impeding access to and egress from the working space?
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B. Where one or more simultaneously opened doors restrict working space access to less than 24 inches wide and 6-1/2 feet high when those doors are or can be opened 90 degrees
The parent rule states the test rather than leaving it to judgement, and it counts doors opened at the same time, which is what a lineup of panels can produce. Notice the doors are assessed at 90 degrees whether or not anybody opens them that far, so an installation is tested against what the doors can do rather than what somebody usually does.
NEC 2026 110.26
19. Which installation does the height subsection excuse from the 6-1/2 foot working space height?
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C. Service equipment or enclosed panelboards not exceeding 200 amperes in existing dwelling units
Three conditions ride together: existing dwelling units, the equipment type named, and the 200 ampere ceiling. Drop any one and the exception does not apply, which is why it is a poor rule of thumb and a good exam item. Two other exceptions cover battery systems on open racks and meters installed in meter sockets.
NEC 2026 110.26(A)(3)
20. Within the required height, what may extend beyond the front of the electrical equipment?
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D. Other equipment or support structures associated with the electrical installation, such as concrete pads, by not more than 6 inches
The allowance is narrow twice over: the thing has to be associated with the electrical installation, and 6 inches is the whole of it. A housekeeping pad under a switchboard is the case it exists for. A duct run across the front of a panel at 6 feet is not associated with anything electrical and fails a dimension almost nobody checks.
NEC 2026 110.26(A)(3)
21. Equipment likely to be serviced while energized is installed above a lay-in ceiling. What opening does the limited access subsection require?
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A. Not smaller than 22 inches by 22 inches
A crawl space gets the larger 22 by 30 opening instead, so the two figures in this subsection go with two different locations. The subsection also carries a width rule of 30 inches or the enclosure width, doors opening 90 degrees, and a space in front meeting the depth table and unobstructed to the floor by fixed cabinets, walls or partitions.
NEC 2026 110.26(A)(4)
22. Under what circumstance does the section permit smaller working spaces by special permission?
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B. Where all exposed live parts operate at not more than 30 volts rms, 42 volts peak, or 60 volts dc
Three figures, all low, and all three describe the same threshold in different measures. Special permission is a defined term, so this is not a decision an installer makes on site. A locked room is an accessibility subject and existing buildings get their own separate permission about condition 2 clearance across an aisle.
NEC 2026 110.26(A)
23. A chilled water line runs above a switchboard, outside the dedicated space but in the same room. What does the code require?
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C. Protection installed to avoid damage to the electrical equipment from condensation, leaks or breaks in the foreign system
Above the dedicated space the answer flips from a prohibition to a condition, and the condition names three failure modes rather than one. Sprinkler protection for the area is separately permitted where the piping complies. And a dropped or suspended ceiling that carries none of the building load is not a structural ceiling, which is what decides where the 6 foot zone ends.
NEC 2026 110.26(E)
24. A mechanical room holds a box of filters on the floor in front of a panelboard and a duct crossing 2 feet above it. How do these sort?
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D. The filters are a working space problem and the duct is a dedicated equipment space problem
Two spaces, two subsections, two kinds of logic, and a stem describing a mechanical room will often plant one of each. The working space is in front of the equipment and may not be used for storage. The dedicated space is the column above it and foreign systems are barred inside the zone. These items are usually written with one loud problem and one quiet one.
NEC 2026 110.26, 110.26(E)
25. What does the section say about the surface a person stands on inside the required working space?
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D. It is kept clear, and kept as flat and level as is practical across the whole of the required depth and width
This one covers grade, floor and working platform alike, and it reaches the whole area the dimensions call for rather than a patch by the door. A trench, a slope to a drain or a run of unistrut across the floor can defeat it without touching any of the three dimensions. Insulating mats are a workplace safety practice rather than a requirement of this section.
NEC 2026 110.26(A)
One question a day keeps the habit, the practice exam runs the clock, and the tools page has the calculators and games.