Support and Securing Practice Questions

A. Securing fastens it so it stays where you put it, and supporting carries its weight

A conduit dropped into open hangers on a trapeze is supported and not secured, since nothing stops it sliding. Strap it at each hanger and one fastener is doing both jobs, which is the ordinary field case and the reason the distinction goes unnoticed on a job. On paper the distinction is the whole item, because the wrong answers are written so the installation looks fine on whichever obligation you happened to check.

NEC 2026 300.13

C. It counts as supported and secured where the holes fall within the article's interval and the cable is fastened within 12 inches of each box or termination

Framing members that the cable passes through do the work of a strap, provided the spacing between them stays inside the interval the article gives and the fastening near each box is still made. An item that mentions joists is not automatically describing a missing strap, which is what the wrong answers are built on. The obligation near the termination is the one that survives, because the fastener nearest a box takes the mechanical abuse.

NEC 2026 334.30

B. No, wiring is not secured to or supported by the ceiling grid system, including its support wires

The grid and its own support wires are off the list, and that is a flat prohibition rather than a spacing question. What is permitted instead is independent support wires added for this purpose, and the article states what makes them independent. A scenario will describe grid wires and purpose-installed wires in language that sounds like either one, so the tell is what the wires were installed for.

NEC 2026 300.13(B)

D. No, cable and conductor wiring methods are not used as a means of support for other cables, conductors, raceways or nonelectrical equipment

Article 300 says raceways may support other things under stated conditions and then says cables may not, full stop. Trade size, fastening and circuit identity change nothing, because the prohibition is about the mechanical character of a cable rather than about a load. This is one of the shortest rules in the article and one of the most often written into a violation scenario.

NEC 2026 300.13

C. Unbroken lengths without couplings may be fished

The tubing article carries two departures from the fastening rule and they are built differently from each other. One is a distance: where structural members do not readily permit fastening within the stated distance of a termination, that distance is increased. The other is a condition with no length attached, covering concealed work in finished buildings or prefinished wall panels, and it is the one this scenario describes.

NEC 2026 358.30(A)

A. Additional support is provided in accordance with the same section

The surface mounting rule asks for the enclosure to be rigidly and securely fastened, and where the surface cannot deliver that, the section sends you back to itself for another method. The 100 cubic inch cap belongs to enclosures held up by entering raceways and to enclosures mounted to suspended ceiling framing, not to surface mounting. Raceway support is a permission with its own conditions rather than a fallback for a soft wall.

NEC 2026 314.23(A)

D. 3 feet

PVC uses the same 3 foot termination distance as the rigid metal and intermediate metal articles, and conduit listed for securing at another distance may follow its listing. What makes PVC different is the support side, where the interval comes off a small table and grows with trade size. The article also opens by requiring the run to be installed so movement from thermal expansion and contraction is permitted, which is a condition on how it is fastened rather than on how often.

NEC 2026 352.30(A)

B. No, an exception releases short sections of raceway used to provide support or protection of cable assemblies

Mechanical continuity between cabinets, boxes, conduit bodies and fittings is the general rule, and the sleeve exception is the departure written for exactly this arrangement. A matching exception sits in the electrical continuity rule for the same reason, so a sleeve is excused twice over. Nothing in either exception turns on a length, which is what the 24 inch option is testing.

NEC 2026 300.14

B. The cable length between the cable entry and the closest cable support is not permitted to exceed 18 inches

The article now caps the developed length of cable between the enclosure and its nearest support, not just the straight-line distance to the fastener, so a run that loops on its way into a box can meet the fastening distance and still fail. That figure is separate from the interval along the run and from the distance to the entry, which gives the section three numbers a question can turn on. The article also says flat cables are not stapled on edge.

NEC 2026 334.30

D. Not more than 4 1/2 feet

This is a length-limited relaxation, so the distance in the stem is there to be used rather than to set the scene. The metal-clad and armored cable articles write their own version of the same permission with their own distances, which is why a figure remembered from one article is unsafe in another. The condition-only relaxation in the same section, covering cable fished between access points in finished construction, is the one with no length attached.

NEC 2026 334.30

C. Within 12 inches of the box and at intervals not exceeding 4 1/2 feet

Armored cable shares the 4 1/2 foot interval with nonmetallic-sheathed cable and uses the same 12 inch figure at a termination. Metal-clad cable, which sits one article away and looks similar on a reel, runs on 6 feet instead, and its 12 inch termination rule reaches only cables of four or fewer conductors no larger than 10 AWG. Two cable articles, two intervals, and an item can be built on either.

NEC 2026 320.30

A. Not exceeding 10 feet, for listed cables in vertical installations

The metal-clad article writes 6 feet as its general interval and then relaxes it to 10 feet for listed cables in vertical installations whose ungrounded conductors are 250 kcmil and larger. Both halves of that condition have to be met, so a vertical run of smaller cable stays on the general interval. The 20 foot figure belongs to exposed vertical risers in the conduit articles, which is a different rule for a different method.

NEC 2026 330.30

D. Not more than 3 feet

The flexibility exception is graded by trade size: 3 feet through trade size 1 1/4, 4 feet for 1 1/2 through 2, and 5 feet for 2 1/2 and larger. Two other exceptions in the same place use 6 feet, one for a tap connection to a luminaire and one for connections within an accessible ceiling, so 6 feet is a real number in this article that belongs to a different condition. Reading the figure without its condition is what these items are built to catch.

NEC 2026 348.30

B. Not more than 100 cubic inches

Article 314 caps the enclosure at 100 cubic inches and then asks that it be fastened to the framing members by mechanical means or by clips identified for that type of framing member and enclosure. Where support wires are used instead, they follow the suspended ceiling rule in Article 300 and are fastened at each end so as to be taut. The same 100 cubic inch cap turns up again for enclosures supported by entering raceways.

NEC 2026 314.23(D)

A. 18 inches

Article 314 splits raceway-supported enclosures into two cases, and the one holding devices, luminaires or lampholders is the stricter of the two at 18 inches. The case without devices uses 3 feet, dropping to 18 inches only where all the conduit entries are on the same side, which is the option written to catch a reader who lands on the wrong subdivision. Both cases cap the enclosure at 100 cubic inches and ask for threaded entries or identified hubs.

NEC 2026 314.23(F)

C. It is supported independently of the outlet box unless the box is listed for at least the weight to be supported

Ceiling outlet boxes are required to carry a luminaire of 50 pounds, and above that figure the luminaire goes on its own support unless the box is listed for the weight and marked on the interior with the maximum it will hold. Read which object the scenario describes before reaching for a number, because a paddle fan of the same weight is answered by a different subdivision with different thresholds. The listing on the box, not the weight alone, is what the answer turns on.

NEC 2026 314.27(A)

C. 80 feet

Supporting the raceway and supporting the conductors inside it are different sections, and the conductor table is read by conductor size and material rather than by raceway size. Copper from 2/0 through 4/0 sits at 80 feet, sizes through 1/0 sit at 100 feet, and aluminum is allowed further in every row because it weighs less. An item about a riser that mentions conductor size is asking about the weight hanging in the pipe rather than about straps.

NEC 2026 300.21(A), Table 300.21(A)

A. 16 feet

The general figure for rigid metal conduit is 10 feet, and the table only comes into play once both conditions in that subdivision are met. On the table the interval grows with trade size: 10 feet through 3/4, 12 feet at 1 inch, 14 feet at 1 1/4 and 1 1/2, 16 feet at 2 and 2 1/2, and 20 feet at 3 and larger. The intermediate metal conduit article sends you to the same table, which is why one lookup answers two methods.

NEC 2026 344.30, Table 344.30(B)

B. 3 feet

PVC is supported off its own table and the spacings are much shorter than for metal conduit, starting at 3 feet for trade sizes 1/2 through 1 and rising to 5, 6, 7 and 8 feet as the conduit gets larger. Reaching for the 10 foot figure that the metal articles use is the single most common error on a PVC support item. Conduit listed for support at other spacings may follow its listing instead.

NEC 2026 352.30, Table 352.30(B)

D. At intervals not exceeding 3 feet, and within 3 feet of each box, cabinet or fitting where it terminates

This article uses the same figure twice, which is unusual and worth noticing, since most method articles give one number for the interval and a different one for the termination. Two exceptions permit 6 feet without securing, one for a tap connection to a luminaire and one for connections within an accessible ceiling, and a third covers concealed work in finished buildings. Where cable ties are used they are listed for the application and for securing and supporting.

NEC 2026 362.30

A. They are installed in addition to the ceiling grid support wires, are distinguishable from them, are secured at both ends, and provide secure support

All four conditions have to be met, and the one people forget is that the wires be distinguishable by color, tagging or some other means, so an inspector can tell at a glance which wires belong to the ceiling. Being added for this purpose and secured at both ends is the substance of the rule; who installed them and what gauge they are is not in it. Two exceptions cover assemblies tested as part of a fire-rated assembly and ceiling systems whose instructions permit branch-circuit wiring.

NEC 2026 300.13(B)

D. A conduit body no larger than the largest trade size of the conduit, an FS or FD single gang device box, or an explosionproof outlet box of any size

The general rule wants two or more conduits threaded wrenchtight into the enclosure or its hubs, and the exception naming what a single raceway may hold up is a short closed list with a size condition on its first entry. It applies only to intermediate metal conduit, rigid metal conduit, PVC, reinforced thermosetting resin conduit and electrical metallic tubing. This is a support rule living inside the box article, which is why it gets missed.

NEC 2026 300.13, 314.23(E)

C. Listed for that purpose, marked on the interior as suitable for it, marked with the maximum weight where that is more than 35 pounds, and supporting no more than 70 pounds

A fan box is a listing question before it is a weight question, and the marking on the interior is where the weight it is good for comes from. The 50 pound figure and the two number 6 screws belong to the luminaire subdivisions, which is exactly the mix-up the wrong answers are built on. A separate paragraph reaches boxes mounted centrally in living and sleeping areas of dwelling units, where the box is either listed for fan support or installed to allow access through it to structural framing.

NEC 2026 314.27(B)

B. Cable ties used for securement and support, and any cable tie fixing device installed with them, are listed and identified for that use

This one is not a distance at all, which is what makes it easy to walk past. The requirement reaches the fixing device as well as the tie, and the same listing language now appears in the cable articles alongside the cable and its fittings. An item that describes what the fastener is rather than how far apart the fasteners are is asking about this.

NEC 2026 300.13

C. Where the raceway or the means of support is identified as a means of support

The subdivision is a short list of four conditions and identification is the first of them. The others are narrow: a raceway carrying power to controlled equipment supporting the Class 2 or Class 3 conductors going to that same equipment's control circuits, a raceway supporting boxes or conduit bodies under 314.23 or luminaires under 410.36(E), and a raceway supporting an equipment bonding jumper associated with the conductors inside it. Relative size and weight appear nowhere in it.

NEC 2026 300.13(C)