Article 314

Which 4-in. square outlet box will be required for three 12 THW and six 12 THHN conductors?

4 x 1 1/2" square box

Each conductor loop that is 12 in. or longer counts as how much volume

two-conductor volume

What is the total box volume for a 4 × 4 × 1½ outlet box and a 4 × 4 × 1½ extension box with a domed cover marked with a 7.50 cu in. volume?

49.50 cu in3

Sizing Outlet Boxes 314.16

Boxes and conduit bodies shall be of an approved size to provide free space for all enclosed conductors.

314.1 Article covers the installation and use of all

Boxes and conduit bodies used as outlet, device, junction, or pull boxes, depending on their use, and handhole enclosures.

Box Fill Calculations : Bonding jumpers originating and terminating in the box

Do not count

Box Fill Calculations : Pigtails originating and terminating in the box

Do not count

Boxes containing 6 AWG and smaller conductors must be sized in an approved manner to provide

Free space for all conductors, devices and fittings

Damp or Wet Locations 314.15

In damp or wet locations, boxes, conduit bodies, outlet box hoods, and fittings shall be placed or equipped so as to prevent moisture from entering or accumulating within the box, conduit body, or fitting.

Conductor insulation ( is OR is not ) a factor for box fill calculations

Is not

Metal Boxes 314.4

Metal boxes shall be grounded and bonded in accordance with Parts I, IV, V, VI, VII, and X of Article 250 as applicable,

Boxes and fittings in damp or wet locations must prevent

Moisture or water from entering or accumulating within the enclosure

Nonmetallic Boxes 314.3

Nonmetallic boxes can only be used with nonmetallic cables and raceways.

Each Splice conductor has how much volume

One conductor volume

Article 314 contains the installation requirements for

Outlet boxes, pull and junction boxes, conduit bodies, and handhole enclosures.

Approved drainage openings not smaller than 3 mm (1⁄8 in.) and not larger than 6 mm (1⁄4 in.) in diameter shall be

Permitted to be installed in the field in boxes or conduit bodies listed for use in damp or wet locations.

Box Volume Calculations 314.16 (A)

The volume of a wiring enclosure (box) shall be the total volume of the assembled sections and, where used, the space provided by plaster rings,

Boxes, conduit bodies and fittings in damp or wet locations must be listed for

Wet locations

Each luminaire stud or hickey counts as

a single conductor volume based on the largest conductor in the box

Cable Clamp Volume 314.16 (B)(2): Where one or more internal cable clamps, whether factory or field supplied, are present in the box

a single volume allowance shall be made based on the largest conductor present in the box.

Raceway and cable fittings including locknuts and bushings

are not calculated for box fill calculations

Cast metal, sheet metal, nonmetallic, and other boxes such as FS, FD, and larger boxes are

are not classified as conduit bodies.

314.16 (B)(2) Conductors that originate within the clamp assembly shall be

included in conductor fill calculations

314.16 (B)(2) A clamp assembly that incorporates a cable termination for the cable conductors shall be listed and marked for use with specific nonmetallic boxes.

listed and marked for use with specific nonmetallic boxes. Conductors that originate within the clamp assembly shall be included in conductor fill calculations covered

Boxes, conduit bodies, outlet box hoods, and fittings installed in wet locations shall

listed for use in wet locations.

Each space within a box with a barrier

must be calculated separately

Each terminating conductor has how much volume

one conductor volume

Each conductor loop less than 12 in. long has how much volume

one-conductor volume

Conductor Volume 314.16 (B)(1) Each conductor that originates outside the box and terminates or is spliced within the box shall be

shall be counted once, and each conductor that passes through the box without splice or termination shall be counted once.

1 or more internal cable clamps count as a

single conductor volume based on the largest conductor in the box

Each loop or coil of unbroken conductor not less than twice the minimum length required for free conductors in 300.14 shall be counted .

twice