All questions and answers are based on the 2011 NEC.

Q. When is a disconnecting means required at a separate building that is supplied by a feeder or branch circuit?

A. A disconnect is required for all conductors that enter or pass through a building/structure [225.31], as shown in the Figure (click here to see Figure).

 

Q. What is counted toward box fill in an outlet box?

A. The calculated conductor volume from the items on the following list are added together to determine the total volume of conductors, devices, and fittings.

  1. Conductor volume. Each unbroken conductor that runs through a box, and each conductor that terminates in a box, is counted as a single conductor volume in accordance with Table 314.16(B). Each loop or coil of unbroken conductor having a length of at least twice the minimum length required for free conductors in 300.14 must be counted as two conductor volumes. Conductors that originate and terminate within the box, such as pigtails, aren’t counted at all. According to 300.14, at least 6 in. of free conductor (measured from the point in the box where the conductors enter the enclosure) must be left at each outlet, junction, and switch point for splices or terminations of luminaires or devices.

Exception: Equipment grounding conductors — and up to four 16 AWG and smaller fixture wires — can be omitted from box fill calculations if they enter the box from a domed luminaire or similar canopy, such as a ceiling paddle fan canopy.

  1. Cable clamp volume. One or more internal cable clamps count as a single conductor volume in accordance with Table 314.16(B), based on the largest conductor that enters the box. Cable connectors that have their clamping mechanism outside of the box aren’t counted.
  2. Support fitting volume. Each luminaire stud or luminaire hickey counts as a single conductor volume in accordance with Table 314.16(B), based on the largest conductor that enters the box. Luminaire stems don’t need to be counted as a conductor volume.
  3. Device yoke volume. Each single-gang device yoke (regardless of the ampere rating of the device) counts as two conductor volumes, based on the largest conductor that terminates on the device in accordance with Table 314.16(B). Each multi-gang device yoke counts as two conductor volumes for each gang, based on the largest conductor that terminates on the device in accordance with Table 314.16(B). A device that’s too wide for mounting in a single-gang box, as described in Table 314.16(A), is counted based on the number of gangs required for the device.
  4. Equipment grounding conductor volume. All equipment grounding conductors in a box count as a single conductor volume in accordance with Table 314.16(B), based on the largest equipment grounding conductor that enters the box. Insulated equipment grounding conductors for receptacles having insulated grounding terminals (isolated ground receptacles) [250.146(D)] count as a single conductor volume in accordance with Table 314.16(B).

Raceway and cable fittings, including locknuts and bushings, aren’t counted for box fill calculations [314.16(B)(2)].

 

Q. Is it acceptable to use a portable cord with male cord caps on both ends to connect a portable generator?

A. No. Attachment plugs must be installed so their prongs, blades, or pins aren’t energized unless inserted into an energized receptacle or cord connector [406.7(B)].