Basement finish rough-in

The answer

The NM cable dropping to the left box is never stapled; it must be secured within 12 in of the box and at intervals of no more than 4.5 ft.

Correct choice: 1. The cable to the left box has no staple within 12 in of the box

NM cable must be supported and secured by staples, straps, listed cable ties, or similar fittings at intervals not exceeding 4.5 ft and within 12 in of every cable entry into a box, and the cable length from the box entry to the first support may not exceed 18 in (334.30). Here the cable leaves the top plate and swings loose across the bay into the box with no fastening at all. Unsecured cable gets pulled when drywall goes up or when a device is pushed in, which loads the conductors at the box entry and can pull the sheath back out of the box (314.17 requires the sheath to extend at least 1/4 in inside the box). The right-hand cable shows the correct pattern.

How to fix it

Code references

• NEC 2023 334.30 — Securing and Supporting

  NM cable shall be supported and secured by staples, listed cable ties, straps, hangers, or similar fittings at intervals not exceeding 1.4 m (4-1/2 ft) and within 300 mm (12 in.) of every cable entry into enclosures such as outlet boxes, junction boxes, cabinets, or fittings. The cable length between the cable entry and the closest cable support shall not exceed 450 mm (18 in.).

  Drills citing 334.30

• NEC 2023 314.17 — Conductors and Cables Entering Boxes, Conduit Bodies, or Fittings

  Cables entering a box shall be secured to it, and an NM sheath shall extend at least 6 mm (1/4 in.) inside the box and beyond any cable clamp. Exception: with single-gang boxes no larger than 2-1/4 x 4 in. mounted in walls or ceilings, securing the cable to the box is not required where the cable is fastened within 200 mm (8 in.) of the box, measured along the sheath, and the sheath extends at least 1/4 in. through a cable knockout.

  Drills citing 314.17

2026 NEC:changed: The 2026 NEC now requires staples, straps, and hangers used to secure NM to be listed (before, only cable ties had to be listed and identified for securement). The 4-1/2 ft, 12 in, and 18 in limits are reported unchanged, so this cable still violates the rule, but the fix should call for listed staples or straps. Confidence: medium

Minnesota

Why the other choices are wrong

• NM cable must be stapled every 12 in along the length of a stud. The maximum interval is 4.5 ft; the 12 in figure applies only to the first support from a box (334.30).
• Plastic boxes are not permitted on framing in a basement. Nonmetallic boxes are permitted with NM cable in dwellings (314.3); a basement is not a special location for boxes.
• Nothing. This installation is compliant. The left cable has no support at all between the top plate and the box, so it fails both the 12 in securing rule and the 18 in cable-length limit in 334.30.