Short answer: Electrical nonmetallic tubing (ENT, Article 362) is a pliable plastic raceway. It may be run exposed in buildings not over three floors above grade, with its other permitted uses listed separately in 362.10 (NEC 362.10(1)(a)), it may not support luminaires or other equipment (NEC 362.12(2)), and it is fastened within 3 feet of each box and at intervals of not more than 3 feet (NEC 362.30(A)). Armored cable (Type AC, Article 320) is a cable with a flexible metal armor. Where the armor ends, a fitting protects the wires from abrasion and an insulating bushing goes between the conductors and the armor (NEC 320.40), and AC cable is not permitted in wet locations (NEC 320.12).
PSI lists raceways and cables in the Wiring Methods and Materials subject area of the Texas Journeyman exam: 10 scored NEC Knowledge questions and 2 scored Calculations questions. PSI does not say how many cover ENT or AC cable. The Texas Journeyman Practice Pack has 1,000 original questions and 10 timed mock exams in the real two-part format, with step-by-step solutions for every calculation. Try free practice questions without signing up. Get the full pack for US$39 with one payment.
Tsai Electro is an independent learning site. Not affiliated with TDLR, PSI or NFPA. We explain the ideas in our own words and do not reproduce NEC text. Check every rule and table value in your own 2026 NEC, and follow your supervisor and the local inspector.
ENT: where it may go
ENT is light, bends by hand and is often called “smurf tube” on site. For exam practice, focus on where ENT is permitted, what it may not support, and how it is fastened.
| Location | ENT permitted? |
|---|---|
| Exposed, in a building not over three floors above grade | Yes (NEC 362.10(1)(a)) |
| Exposed, in a building over three floors above grade | No, unless another item in 362.10 allows it |
| Concealed in walls, floors and ceilings | Yes, under the conditions in 362.10 |
| Encased in poured concrete | Yes, under the conditions in 362.10 |
| Above a suspended ceiling | Only where the ceiling meets the conditions in 362.10 |
| Holding up a luminaire or other equipment | No (NEC 362.12(2)) |
Read the floor count carefully. For the exposed-work permission, “not over three floors” means a three-story building is in and a four-story building is out. For other installations, check the rest of 362.10.
Worked example: how many straps on an ENT run
A straight ENT run goes 21 feet between two boxes, with no other supports. Find the minimum number of straps. It must be fastened within 3 feet of each box and at intervals of not more than 3 feet (NEC 362.30(A)).
- First and last straps. One 3 feet from the first box, one 3 feet from the second box: at 3 ft and 18 ft.
- Between them. 18 − 3 = 15 feet. At 3-foot intervals: 15 ÷ 3 = 5 spaces.
- Count. 5 spaces need 6 straps in a row: at 3, 6, 9, 12, 15 and 18 ft. 6 straps.
AC cable: three rules at the armor
- Ending the armor. Where AC cable terminates, a fitting protects the wires from abrasion, and an insulating bushing (the red “anti-short” bushing) or equivalent goes between the conductors and the armor (NEC 320.40).
- No wet locations. AC cable is not permitted in wet locations (NEC 320.12). Outdoors or in a wet area, pick a wiring method that is permitted there.
- In attics. Where the attic is not reached by permanent stairs or ladders, the protection rule in this section applies only within 6 feet of the nearest edge of the scuttle hole or attic entrance; other cable protection rules still apply (NEC 320.23(A)(2)). Check 320.23(A) in your NEC for the guard strip rules where the attic is reached by permanent stairs or ladders. Type NM cable in attics follows the same 320.23 rules, which 334.23 points to; the NM article itself is in NEC 334, 330 and 400 cables and cords.
Check yourself
- Can ENT be run exposed in a five-story building? Not under the three-floor item. Check whether another item in 362.10 applies.
- An ENT run is 15 feet between boxes. How many straps at the 3-foot maximum? At 3, 6, 9 and 12 ft: 4 straps. Each end gap and each interval is 3 feet or less.
- Is AC cable permitted in a wet location? No.
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Find 362 and 320 faster on exam day
NFPA 70, National Electrical Code, 2026 Edition (softcover). Highlight the exposed-use limit in 362.10, the strap spacing in 362.30(A) and the attic rule in 320.23(A), so each one is quick to find from a question. The Texas exam is open book. PSI allows a soft-bound NEC with highlighting, underlining and notes made in advance. Loose-leaf, spiral-bound and ring-bound copies are not allowed, and only permanent index tabs made or supplied by the NEC publisher are permitted; homemade and third-party tabs are not.
FAQ
Can ENT be run exposed?
Yes, in buildings not over three floors above grade. Other items in 362.10 cover concealed work, concrete encasement and suspended ceilings.
How often is ENT strapped?
Within 3 feet of each box and at intervals of not more than 3 feet.
Can ENT hold up a light fixture?
No. ENT may not be used to support luminaires or other equipment.
What goes on the end of AC cable?
A fitting that protects the wires from abrasion, and an insulating bushing or equivalent between the conductors and the armor.
Can AC cable be used outdoors in wet locations?
No. AC cable is not permitted in wet locations.
Sources checked October 2026
- PSI Candidate Information Bulletin, Texas electrician examinations (updated September 15, 2026): https://test-takers.psiexams.com/api/content/bulletin/1682
- NFPA 70, National Electrical Code, 2026 Edition, Articles 320, 334 and 362
