NEC 314.16(B)(1)-(B)(5)
What it means on the job
This box is OVERFILLED, so it is not compliant. Per NEC 314.16(B), each #14 AWG insulated conductor counts as 2.0 cu in (6 conductors = 12.0). Per 314.16(B)(2) all internal clamps together count as one allowance (2.0). Per 314.16(B)(5) all equipment grounding conductors together count as one allowance (2.0). Critically, per NEC 314.16(B)(4) a device yoke counts as TWO volume allowances based on the largest conductor connected to it: 2 x 2.0 = 4.0 cu in — not one. Total = 12.0 + 2.0 + 2.0 + 4.0 = 20.0 cu in required, which exceeds the 18.0 cu in box by 2.0 cu in. A larger box (or fewer conductors) is required.
Tested in 1 CraftIQ puzzle
- code-checkBox Fill Calculation
Related NEC sections
NEC 250.53(D)(2)
A metal underground water pipe electrode must be supplemented by an additional grounding electrode. It cannot serve as the sole grounding electrode because plastic pipe repairs can interrupt the path.
NEC 250.64(C)
Grounding conductor splices must use listed connectors such as split bolts, compression connectors, or exothermic welds. Electrical tape alone is not a listed grounding connection method.
NEC 314.16(B)
Box fill calculations per NEC 314.16 require each #12 conductor to have 2.25 cu in. An overfilled box causes conductor damage, overheating, and difficulty making proper connections.
NEC 314.29
All junction boxes, pull boxes, and conduit bodies must remain accessible without removing any part of the building structure. Boxes cannot be buried behind walls, ceilings, or floors.
NEC 358.26
The maximum number of bends between pull points cannot exceed 360 degrees (four 90-degree bends). Exceeding this limit makes wire pulling extremely difficult and risks damaging conductor insulation.
NEC 400.8
Window AC units must be plugged directly into a wall outlet, never an extension cord. Extension cords cause voltage drop, overheating, and are a fire hazard with high-amperage equipment.
CraftIQ explanations are original educational commentary written in trade language and verified against the cited standards. Always confirm requirements against the code edition adopted by your jurisdiction — this is training material, not a substitute for the code book or your AHJ.