10.1 PVC and ENT

10.1 PVC and ENT

Quick Answer: Rigid PVC Conduit is Article 352; Electrical Nonmetallic Tubing (ENT) is Article 362. Fasten PVC within 3 ft of boxes/cabinets and support per Table 352.30; use expansion fittings where temperature swing would stress the run (352.44). Fasten ENT within 3 ft and support every 3 ft max (362.30). Always pull a wire-type EGC—PVC and ENT never replace the equipment grounding conductor the way EMT/RMC can under 250.118.

On the Arkansas Journeyman Electrician exam (Prov / ADLL, NEC 2023, 60 questions, 3 hours, 70% pass), Raceways and Enclosures is 8 items. After metal raceways, Prov loves nonmetallic contrast questions: wrong support interval, Schedule 40 where Schedule 80 is required, ENT outdoors without listing, or forgetting the EGC entirely. This section trains you to open 352 or 362 first, then apply the right support and use rules.

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PVC vs ENT — pick the correct article

If the stem says “PVC conduit,” “Schedule 40,” or “expansion fitting,” stay in 352. If it says “smurf tube,” “ENT,” or “corrugated nonmetallic,” stay in 362. Do not apply EMT’s 10 ft support rule to either.

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Rigid PVC — uses permitted (352.10)

352.10 permits Rigid PVC for exposed and concealed work in many environments when the conduit and fittings are suitable:

• Dry, damp, and wet locations (PVC is a workhorse outdoors and underground).
• Concrete embedment and direct burial (with burial depth from Table 300.5 and any listing/coating requirements).
• Corrosive atmospheres where PVC is compatible with the chemicals present.
• Cinder fill and similar environments where metal conduit would need special protection.

Schedule 40 vs Schedule 80: Both are Rigid PVC Conduit under Article 352. Schedule 40 is the default for underground, concrete, and protected indoor runs. Where the Code or the installation is subject to physical damage, Schedule 80 (thicker wall) is the usual permitted answer when PVC is still allowed. Prov stems that describe unprotected garage columns, warehouse posts, or exposed exterior walls often want Schedule 80—or a metal raceway instead.

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Rigid PVC — uses not permitted (352.12)

352.12 is high-yield. PVC shall not be used:

• In hazardous (classified) locations, except as Chapter 5 expressly permits.
• For support of luminaires or other equipment (PVC is a raceway, not a structural member).
• Where subject to ambient temperatures exceeding the listing (commonly discussed around 50°C / 122°F limits for the conduit material—verify the marking/listing).
• In theaters and similar locations except as permitted elsewhere.
• Where physical damage conditions exceed what Schedule 80 and the article allow—do not force PVC into a forklift aisle when RMC is the honest answer.

Exam habit: First ask “Is PVC even permitted here?” Then ask “Schedule 40 or 80?” Then ask “Where are the straps and expansion fittings?”

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Securing, supporting, and expansion — 352.30 / 352.44

Termination fastening

Securely fasten PVC within 3 ft of each outlet box, junction box, device box, cabinet, conduit body, or other termination (352.30). That number matches EMT’s termination rule—but the run support is not the same.

Table 352.30 support spacing

Along the run, support PVC at intervals not exceeding the distances in Table 352.30. Smaller trade sizes need closer supports; larger sizes may go farther. Open the table on exam day—do not memorize every row, but know that PVC support is trade-size-dependent and generally tighter than EMT’s flat 10 ft for many sizes.

Expansion fittings — 352.44

PVC expands and contracts with temperature far more than steel. 352.44 requires expansion fittings where temperature change is expected to cause expansion/contraction that would damage the raceway or connected equipment. Long outdoor risers, rooftop runs, and runs from conditioned space to hot attics are classic triggers. The exam may give a temperature delta and ask whether an expansion fitting is required—when in doubt on a long exposed PVC run with wide ambient swing, the Code answer is to provide listed expansion fittings as calculated/required.

Worked support examples

Example A: ¾ in Schedule 40 PVC from a panel to a junction box in a dry warehouse, 40 ft straight. Fasten within 3 ft of each end; place intermediate supports per Table 352.30 for ¾ in (commonly 3 ft spacing on that row—confirm in your 2023 book). Do not space straps every 10 ft like EMT.

Example B: Schedule 80 PVC riser on an exterior wall from underground to a meter enclosure. Use Schedule 80 where physical damage is a concern; fasten within 3 ft of the enclosure; consider 352.44 expansion if the riser sees large seasonal temperature change.

Example C: PVC stub-ups in a concrete slab. Embedment is permitted; protect above-grade portions from damage (often transitioning to Schedule 80 or metal where exposed to abuse).

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Bends, joints, and grounding with PVC

Field bends use heat blankets or hot boxes so the internal diameter is not reduced (352.24). Total bends between pull points still respect the 360° family of raceway bend limits (352.26). Solvent-cement joints per manufacturer instructions; listed adapters connect PVC to boxes and to metal raceways.

Critical grounding rule: PVC is nonmetallic. It cannot serve as an EGC. Pull a green or bare equipment grounding conductor sized from Table 250.122, or meet another Code-compliant grounding method. Metal boxes connected only by PVC need bonding jumpers/EGCs landed correctly—do not assume the raceway bonds anything.

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ENT — Article 362 essentials

ENT is a pliable corrugated raceway used heavily in wood-frame and concrete construction for branch circuits. 362.10 permits ENT in many dry, concealed locations and in poured concrete under stated conditions. 362.12 rejects ENT where subject to physical damage, in theaters (with limited exceptions), in direct earth burial (unless Chapter 3/listing paths apply—generally ENT is not the underground method), and in wet locations unless the ENT and fittings are listed for wet use.

Support — 362.30 (memorize the contrast)

• Securely fastened within 3 ft of terminations.
• Supported at intervals not exceeding 3 ft.

Horizontal runs through framing with openings ≤ 3 ft apart can count as supported, but you still need termination fastening. Finished-construction exceptions exist in the article text—read them; do not invent a general “no straps needed” rule.

Worked ENT examples

Example D: ENT home-run in 2×4 studs with holes every 16 in. Framing openings closer than 3 ft support the tubing; still fasten within 3 ft of each box.

Example E: ENT exposed across a basement ceiling joist bay spanning 5 ft with no intermediate fastening. That violates the 3 ft support interval unless an Exception clearly applies—add a strap.

Example F: ENT used outdoors exposed to weather without wet-location listing. Reject under 362.12 / suitability rules; choose PVC, LFNC, or another wet-rated method.

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Common Prov traps

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Timed open-book tips

Tab 352.10, 352.12, 352.30, Table 352.30, 352.44, 362.10, 362.12, and 362.30. Decision tree: (1) PVC or ENT? (2) Is the use permitted? (3) Schedule 40 vs 80 if PVC and damage is in play? (4) Termination 3 ft + correct run supports? (5) Expansion needed? (6) Wire-type EGC pulled? That sequence clears most nonmetallic raceway items among Arkansas Prov’s eight Raceways and Enclosures questions.