Written against the 2026 NEC and checked section by section, September 2026
Agricultural Buildings Practice Questions
Article 547 is a scope article before it is a requirements article, and most items on it are decided by whether the described conditions exist at all. These questions lean on 547.1 and 547.5 for scope, on 547.20 through 547.31 for the wiring and equipment rules, and on 547.40 through 547.44 for the distribution point and the equipotential plane. Section numbers are the 2026 addresses, which are not the ones most published material still uses.
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 agricultural buildings study page first if the topic is new to you.
1. A farm office with a desk and a copier sits at one end of a hog barn. It has no feed dust, no ammonia and it is never washed down. Which rules govern the wiring in that office?
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C. The articles that would apply to any other office of the same kind
The scope is written around conditions, not around what a building is called or who owns it. With no dust, no corrosive atmosphere and no periodic washing, the article hands that space back to the rest of the code. Reading the building name instead of the described conditions is what produces the first choice.
NEC 2026 547.1, 547.5
2. Which condition named in the scope of Article 547 pulls a poultry confinement house into the article?
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A. Litter dust or feed dust that may accumulate
The first half of the scope is about dust, and it names litter dust and feed dust, mineral feed particles included, in poultry, livestock and fish confinement systems. Floor area, service rating and ownership are not scope tests anywhere in the article. If the dust is not there, neither is the article.
NEC 2026 547.1(A)
3. The second half of the Article 547 scope covers a corrosive atmosphere. Which of these is one of the conditions it names?
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D. Poultry and animal waste producing corrosive vapors
The scope lists the corrosive conditions directly, and animal waste giving off corrosive vapors is the first of them, alongside corrosive particles combining with water and areas kept damp and wet by periodic washing for cleaning and sanitizing. Coastal salt and generator exhaust are real corrosion problems that this article does not name. Read the list rather than reasoning from what corrodes metal.
NEC 2026 547.1(B)
4. Which wiring method appears on the list Article 547 permits in the areas it covers?
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B. Jacketed Type MC cable
The permitted list runs Type UF, Type NMC, copper Type SE cable, jacketed Type MC cable, and raceways identified for the locations in the scope. Jacketed is the word doing the work, because an unjacketed assembly has nothing between the corrosive atmosphere and the metal. Type NM reads close enough to Type NMC that it is the choice most candidates reach for.
NEC 2026 547.20
5. Article 547 requires cables to be secured within what distance of each cabinet, box or fitting?
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A. 8 inches
The mounting rule sets 8 inches, measured to each cabinet, box or fitting. That is tighter than the securing intervals people carry over from the cable articles, and this article states it in one short sentence. Answering from the wiring method article instead of from 547.21 gives you 12 inches.
NEC 2026 547.21
6. Nonmetallic boxes, fittings, conduit and cables are mounted flat against a barn wall that Article 547 covers. What happens to the quarter inch airspace the general corrosion rule asks for?
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C. Mounting directly to the surface is permitted without it
The mounting section lets those nonmetallic items go straight onto any building surface covered by the article without keeping the airspace the general rule asks for. The reasoning is that nonmetallic parts are not what the airspace was protecting. Carrying the general rule in unchanged is the trap, because it sends you hunting for a spacer this article does not want.
NEC 2026 547.21, 300.8(D)
7. A hog pen is normally dry but gets sprayed with water every week for cleaning. How does Article 547 treat that area for boxes, conduit bodies, enclosures and fittings?
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B. As a wet location, so those items are listed for wet locations
The damp and wet section reaches a normally dry or damp area that is periodically washed or sprayed and treats it as wet, which pushes boxes, conduit bodies, enclosures and fittings into wet location listing. Weekly hosing is enough to get you there. Calling it damp because the water is intermittent is the reading the section was written to close off.
NEC 2026 547.23
8. Wet dust and corrosive vapors are present around a feed room panel inside the scope of Article 547. What does the article require of the enclosures, boxes, conduit bodies and fittings there?
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A. Corrosion resistance suitable for the conditions
The corrosive atmosphere section asks for corrosion resistance properties suited to the conditions and points at the enclosure type table for the designations that go with them. It sets no metal thickness and it classifies nothing. Treating a dusty room as automatically classified is the error that sends people to Article 500 when no location has been classified.
NEC 2026 547.24
9. A grain auger motor in a covered area needs a flexible connection. Which of these does Article 547 permit for that purpose?
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D. Liquidtight flexible nonmetallic conduit with listed fittings
The flexible connection list is short: dusttight flexible connectors, liquidtight flexible metal conduit with listed fittings, liquidtight flexible nonmetallic conduit with listed fittings, and hard usage cord terminated with listed dusttight cord connectors. Plain flexible metal conduit is not on it, and the cord choice fails on its connector rather than on the cord. The listing words in each entry are the part being tested.
NEC 2026 547.25
10. A lunchroom shares a wall with a livestock confinement area in the same building. Where does Article 547 refuse to allow nonmetallic cable?
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A. Concealed within the walls and above the ceilings
The physical protection section blocks nonmetallic cable from being concealed in the walls and above the ceilings of offices, lunchrooms and similar areas that adjoin livestock confinement areas. Rodents chew the jacket and the insulation, and nobody sees it happen behind a finished surface. The rule is about concealment rather than about the room, so banning the cable from the whole lunchroom overshoots it.
NEC 2026 547.26
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. A separate equipment grounding conductor that is not part of a listed cable assembly is run underground inside an area covered by Article 547. What does the article require of it?
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D. It has to be insulated
The section asks for insulation on that conductor, because a bare grounding conductor sitting in wet corrosive soil does not stay a reliable path for long. Size still comes from the ordinary grounding table, and this sentence does not restrict the material. Upsizing is the plausible wrong answer because it sounds like something a special occupancy article would do.
NEC 2026 547.27
12. Inside the scope of Article 547, the ground-fault protection requirement is aimed at which receptacles?
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C. 125 volt alternating current receptacles rated 15 and 20 amperes
The section names 125 volt alternating current receptacles rated 15 and 20 amperes, in areas requiring an equipotential plane, outdoors, damp or wet locations and dirt confinement areas for livestock. It is written from the negative direction, which is why working it from a summary goes wrong so often. A receptacle outside that voltage and ampere description is not what this sentence reaches.
NEC 2026 547.28
13. Parts of an agricultural building that fall outside the scope of Article 547 still need ground-fault protection. Which rule supplies it?
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B. The general rule for other than dwelling units
The section hands those areas to the general ground-fault rule for other than dwelling units and stops there. That pointer is also the proof that an agricultural building routinely contains areas the article does not reach. Assuming the article covers the whole building is the reading it exists to correct.
NEC 2026 547.28, 210.8(B)
14. What does Article 547 require of motors and other rotating machinery in the areas it covers?
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A. Totally enclosed, or designed to keep dust, moisture and corrosive particles out
The motor sentence asks for a totally enclosed machine or one designed to minimize the entrance of dust, moisture and corrosive particles. It is about the frame rather than about the circuit feeding it. Reaching for a hazardous location rating is the common overshoot, because barn dust is combustible without the location having been classified.
NEC 2026 547.30
15. A luminaire in a wash bay gets hit by condensation and cleaning solution. What does Article 547 require of it?
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D. Listing for wet locations
The luminaire section has three parts, and the water part asks for wet location listing where condensation, building cleansing water or solution reaches the fixture. The guard belongs to the separate physical damage part, so it is a real requirement answering a different question. Matching the hazard in the stem to the right subdivision is most of the work here.
NEC 2026 547.31(C)
16. A farm already has one yard pole feeding four livestock barns. The owner wants a second yard pole with its own meter for a new barn across the property. What does the supply section say?
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C. More than one distribution point on the same premises is permitted
The section requires livestock buildings and structures on the premises to be supplied from a distribution point, then says outright that more than one on the same premises is allowed. The picture of a single handle that kills a whole farm is one common arrangement rather than a requirement. The first choice is what a candidate marks after reading about the site isolating device and inferring a single point from it.
NEC 2026 547.40
17. When does Article 547 require a site isolating device at the distribution point?
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B. Where two or more buildings or structures are supplied from that point
The trigger is two or more buildings or structures fed from the distribution point. One structure on its own does not bring the device with it. Load and distance are the kinds of numbers a candidate expects to find in a rule like this, which is exactly why they work as distractors here.
NEC 2026 547.41(A)(1)
18. The operating handle for a site isolating device is mounted so it can be worked from grade. In its highest position, how far above grade or a working platform may that handle be?
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D. 6 feet 7 inches
The accessibility item sets 6 feet 7 inches, which is 2.0 meters, as the ceiling for the handle in its highest position. The device itself is pole mounted well above that, so the handle is the part this rule is about. Confusing the handle height with the reach and working space dimensions in Article 110 produces every one of the shorter answers.
NEC 2026 547.41(A)(7)
19. Does the site isolating device at a distribution point have to provide overcurrent protection?
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C. No, the section states that it is not required to
The section says the device is not required to provide overcurrent protection, which is what makes it an isolating device rather than a service disconnect. Its rating still has to cover the calculated load, and that sits as a separate item in the same list. Fusing the rating requirement and a protection requirement together is where the first two choices come from.
NEC 2026 547.41(A)(6)
20. How high does a pole mounted site isolating device have to sit?
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B. Not less than the clearance the overhead conductor rules require for the conductors it supplies
The location item ties the height to the overhead clearance rules for the conductors the device supplies rather than printing a figure of its own. That way the answer moves with the span and with what runs underneath it. A single fixed number looks like the answer a rule of this kind would give, which is why it is offered.
NEC 2026 547.41(A)(2), 230.24
21. A site is fed from three distribution points. What does Article 547 require at each of them?
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A. A permanent plaque or directory naming the other points and what each one serves
The identification section asks for a permanent plaque or directory at each distribution point, giving the location of the others and the buildings each one serves. It is a wayfinding requirement for whoever shows up in the dark. Nothing in the article ties three points together under one common disconnect.
NEC 2026 547.43
22. Indoors, where does Article 547 require an equipotential plane?
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B. In confinement areas with concrete floors where metallic equipment that could become energized is accessible to livestock
Three things have to be true at once: a confinement area, a concrete floor, and metal that could become energized within reach of the animal. Drop any one of them and the requirement is not triggered. The first choice is the answer you get by remembering the concrete and forgetting the metal.
NEC 2026 547.44(A)(1)
23. An equipotential plane is bonded back to the grounding system. What does the article say about that bonding conductor?
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C. Solid copper, insulated, covered or bare, not smaller than 8 AWG
The bonding sentence sets solid copper and a floor of 8 AWG, and it lets the conductor be insulated, covered or bare. Solid is the word people skip and insulation is the word people add. The destination matters as much as the conductor: the grounding electrode system, or an equipment grounding terminal in an enclosed panelboard of the grounding system that goes with the plane.
NEC 2026 547.44(B)
24. A candidate who learned pool bonding first is asked where the farm equipotential plane connects. What is different about the farm rule?
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D. The farm article names the destination and makes you run a conductor to it
The pool section says the bonding conductors are not required to be extended or attached to remote panelboard enclosures, service equipment or electrodes, because the connection happens anyway through the pump circuit. The farm section leaves nothing to chance and names the grounding electrode system or an equipment grounding terminal in an enclosed panelboard. Same physics, opposite wording, and item writers pair them on purpose.
NEC 2026 547.44(B), 680.26(B)
25. Structural steel is missing from a slab, so a copper grid is installed for the equipotential plane. What spacing does the article set for that grid?
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A. A 12 inch by 12 inch pattern, with a 4 inch tolerance
The copper grid is built from bare solid copper no smaller than 8 AWG, arranged on a uniformly spaced perpendicular pattern 12 inches each way with a 4 inch tolerance, bonded at every crossing. Those crossings are joined with listed splicing devices or exothermic welding, not with taped wraps. Halving or doubling the spacing is the quickest way to lose this one.
NEC 2026 547.44(C)(2)
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