Expansion fittings on the Texas exam, and the quarter inch that settles them

What the exam asks about it

Our question bank runs to 500 items and 51 of them sit in the conduit and raceway area. Three of those 51 are expansion arithmetic. A fourth item, over in the wiring methods area, puts an expansion fitting among the wrong answers for feeder conductors run out along a floating pier, where the structure moves in every direction and Article 555 answers with portable power cable. That is a small share of a paper, and a dependable one, because the arithmetic is short enough to sit inside a timed item.

The published blueprint says where the weight falls. Electrical wiring methods and materials carries 10 of the 56 scored items on the journeyman knowledge portion, tied for the heaviest single area, and 2 of the 24 scored items on the calculations portion. An expansion question can reach you from either half, and since March 2025 the two halves have been scored separately.

The pass rates behind that split are worth holding onto. In fiscal year 2025 the journeyman calculations portion passed 1,301 of 6,328 candidates, which is 20.56 percent, while the knowledge portion passed 1,402 of 5,731, or 24.46 percent. Candidates lose this license on arithmetic more often than on code knowledge, and an expansion item is arithmetic wearing a wiring methods label.

The step that decides the arithmetic

Both calculation items in the bank hand you a run length and a length change per 100 feet, and both are settled by the same step. A straight run of rigid polyvinyl chloride conduit measures 320 feet between the items that anchor it, and the table figure for the temperature change involved is 3.05 inches per 100 feet. Scale the figure by the run: 320 feet is 3.2 hundreds of feet, and 3.2 times 3.05 gives 9.76 inches of movement.

Each wrong answer is a different mishandling of that one step. One reads 0.98 inches, which is the run scaled in thousands of feet. One reads 19.52 inches, the right figure doubled by a habit carried over from voltage drop, where the conductor goes out and comes back. The third prints 3.05 inches, the table figure used as though every run were 100 feet long.

The second item is built to land just over the line on purpose. A 22 foot run with a table figure of 1.15 inches per 100 feet gives 0.22 times 1.15, which is 0.253 inches. NEC 352.44(A) puts a fitting in the run where the calculated change reaches a quarter inch, and 0.253 clears it. Two of the distractors come from reading the threshold as a figure the calculation has to beat by some margin, and from an assumption that a run under 25 feet is excused. There is no length below which the rule switches off, and the calculation decides.

Travel, and where you set it

The third arithmetic item leaves the table behind. An expansion fitting with 6 inches of total travel is installed and set at mid travel, and the question asks how much movement it accommodates in each direction. Total travel is the whole span the fitting can move through, so setting it at the middle divides that span evenly and gives 3 inches of expansion with 3 inches of contraction.

All three wrong answers are arithmetic done to the same number: the travel doubled to 12 inches, the 6 inches read as the amount available in each direction, and the travel quartered to 1.5 inches. It is a single division dressed as a code question, and it is the kind of mark a rushed candidate hands back.

Half of the value here follows you onto the job, because a fitting is set against the temperature on the day it goes in. One installed on a hot August afternoon and set at mid travel carries more room to contract than the run will ever use, and less room to expand than it may need. The movement also gets worked out before the fitting is bought, since a 9.76 inch calculated change asks for a fitting selected for that travel.

Which thing is doing the moving

Almost every expansion item turns on one question, which is what is doing the moving. Separate rules answer separate movements, and the options are usually written so the correct answer for the rule you skipped sits right there looking plausible.

Article 300 was reworked for the 2026 edition and these sections moved down two places. The structural joint rule that sat at 300.4(H) in the 2023 book is at 300.6(H) now, and the general expansion sentence moved from 300.7 to 300.9(B). A tab set cut for the older edition lands you two sections short, on real code text under a heading that gives no hint you are in the wrong place. Our page on burial depth and cover works through the same renumbering on the underground side, where it bites harder.

The item wearing a fitting costume

A metal fitting that lets a raceway slide has opened the metal path that fault current would otherwise take, so a second rule follows the first from a different chapter. NEC 250.98 has expansion, expansion-deflection and deflection fittings and telescoping sections of metal raceways made electrically continuous by equipment bonding jumpers or other approved means.

Item writers like that pairing, because a candidate can answer half of it and feel finished. The scenario describes a metal raceway crossing a joint, the options offer a fitting and a jumper in various combinations, and the option that installs the fitting and stops looks complete sitting there on the screen. Where a scenario puts metal and movement in the same sentence, part of the answer lives in Article 250, and the grounding and bonding area carries the reasoning behind why the jumper is the second half of the job.

What a Texas run actually sees

The temperature input is where a Texas run separates itself from the weather report. A dark conduit on a south facing wall in July runs far hotter than the air moving past it and is back near ambient before dawn, so the swing the raceway sees is wider than anything published for the city it stands in. The same length of pipe on the north side of that building lives in a narrower band and can sit under the threshold while its twin clears it.

Earth movement is the other piece with a Texas accent. NEC 352.44(B) names settling or movement first and frost heave second, which suits a state where expansive clay under a slab moves a good deal more than frost ever will. The fitting that subsection asks for goes above grade on the riser, at the point where buried pipe lands in fixed equipment, because that joint is what tears when the soil lifts and drops. A riser into a pad mounted enclosure is the everyday version of the scenario, and the general arrangement rule at NEC 300.7(J) reaches the same problem for direct buried conductors, raceways and cables of any material.

What it costs on the job

A fitting absorbs movement only where the raceway on the piston side of it can slide. NEMA guidance on PVC expansion fittings has the barrel clamped solidly while the conduit entering it is mounted loosely enough to move, and an installation that straps both sides down hard at every support has bought a fitting that does nothing while the movement goes back into the terminations. That failure is invisible on the day it is made and turns up later as a cracked coupling or a broken box entry, which is rework somebody pays for twice.

Support is in play whenever expansion is. PVC is fastened near each box, conduit body and other termination, and its support spacing between those points varies with trade size, so Article 352 carries a small table at 352.30 where other articles carry a single figure. A long exposed nonmetallic run has two sections standing behind it, and an inspector walking that run will look at both. Our page on support and securing sets out how those two distances are measured and which one an item is aiming at.

What to do before test day

The Texas exam is open book and you bring your own copy of the code. 16 TAC 73.100 adopts the 2026 National Electrical Code effective 1 September 2026, and the PSI candidate information bulletin puts the examinations on that edition from the same date. Our page on which edition applies covers what the switch does to your license, which is very little, and what it does to your tabs, which is more.

Four things are worth an hour of study time here.

• Work half a dozen scaling problems with the units written at every step, until the hundreds of feet step stops being a decision you make under pressure.
• Read NEC 352.44 end to end so subsection (B) stops arriving as news.
• Tab NEC 250.98, because that is where a bonding item hides when the stem is all about a fitting.
• Tab NEC 300.6(H) and NEC 300.9(B) by title, since both moved two sections this cycle.

Pacing matters on the calculations portion, where 110 minutes covers 26 items at about 4.2 minutes each. An expansion item worked cleanly takes under two of those minutes, and the time it hands back pays for a service calculation later in the paper. The retake fee is $78 for the journeyman, so the minutes are worth protecting.

The table lookup and the full worked arithmetic live in the question set. The thirty free timed questions here mix expansion items in with the rest of the conduit area, so you meet them the way the exam serves them, with a clock running.

Questions people ask

When does a PVC run need an expansion fitting in Texas?

When the calculated length change reaches a quarter inch. NEC 352.44(A) asks for expansion fittings on PVC conduit to compensate for thermal expansion and contraction where the length change, worked from the expansion table in that subsection, is expected to be a quarter inch or greater in a straight run between securely mounted items such as boxes, cabinets, elbows or other terminations. There is no run length in feet in that sentence and no trade size either. The inputs are the temperature change the run will see in service and the length of the straight run between the points that anchor it.

How do you scale the expansion table figure to your run?

The table figure is stated per 100 feet, so convert your run into hundreds of feet and multiply. A 320 foot run is 3.2 hundreds, and at a table figure of 3.05 inches per 100 feet that comes to 9.76 inches. A 22 foot run is 0.22 hundreds, and at 1.15 inches per 100 feet it comes to 0.253 inches, which clears the quarter inch threshold. Three wrong answers live around that one step: scaling in thousands, doubling the result out of voltage drop habit, and comparing the raw table figure against the threshold with no scaling at all.

How much movement does a 6 inch expansion fitting take?

Three inches in each direction, where the fitting is set at mid travel when it is installed. Total travel describes the whole span the piston can move through, so setting it at the middle splits that span evenly between expansion and contraction. The bank item on this offers 12 inches, 6 inches and 1.5 inches as the wrong answers, which are the same number doubled, read as the per direction figure, and quartered. Setting matters as much as selection: a fitting set at mid travel on a hot afternoon holds contraction room the run will never use.

Do metal raceways ever need expansion fittings?

Yes, where they are necessary. NEC 300.9(B) has raceways provided with expansion, expansion-deflection or deflection fittings where necessary to compensate for thermal expansion, deflection and contraction, and that sentence reaches every raceway type in the book with no table and no threshold printed behind it. Steel moves about a sixth as much as PVC for the same temperature change, which is why the arithmetic sits in the nonmetallic articles. Then NEC 250.98 arrives: fittings of that kind and telescoping sections of metal raceway are made electrically continuous by equipment bonding jumpers or other approved means.

What is the difference between 352.44 and 300.6(H)?

One answers a raceway that moves and the other answers a building that moves. NEC 352.44(A) is thermal, it has a table and a quarter inch threshold, and the arithmetic decides whether a fitting goes in. NEC 300.6(H) covers a raceway crossing a structural joint intended for expansion, contraction or deflection in a building, a bridge, a parking garage or another structure, and nothing about it is calculated. The joint is designed into the structure, the raceway crossing it takes a listed fitting or other approved means, and the word listed does real work in the answer choices.

Where does the expansion rule sit in the 2026 code book?

NEC 352.44 stayed where it was, with the calculated threshold and the expansion table at subsection (A) and earth movement at subsection (B). Article 300 is the part that moved. Structural joints went from 300.4(H) in the 2023 book to 300.6(H), and the general expansion sentence went from 300.7 to 300.9(B), which also pushed the underground material from 300.5 to 300.7. Texas adopted the 2026 edition effective 1 September 2026 under 16 TAC 73.100, and the examinations moved to it on the same date, so an older tab set costs you time on every Article 300 lookup.