Unit 3: Boxes and Enclosures
for Boxes and Enclosures Supported by Wood brackets, they must have a cross section of at least how many inches, according to article 314,23,B,2
1 inch by 2 inches
Nails can attach brackets on the outside of the enclosure or extend through the interior within how many inches of the back or ends of the enclosure?
1/4 inches
The cable sheath shall extend into the box at least how many inches through the cable knockout or opening
1/4 inches
Nonmetallic-sheathed cable shall be secured within how many inches of every box?
12 inches, article 334,30
Section 314,23,F, Exception number 2, permits unbroken length(s) of rigid or intermediate metal conduit to support a box used for luminaire or lampholder support where all of the following conditions are met, name the conditions.
1; The length of conduit extending beyond the last point of securely fastened support does not exceed 3 fit, 2; A luminaire supported by a single conduit does not exceed 1 fit. in any direction, from the point of conduit entry, 3; The weight supported by any single conduit shall not exceed 20 pounds. 4; At the luminaire end, each conduit (if more than one) is threaded wrench tight into the box or wiring enclosure or into identifi ed hubs. 5; Where accessible to unqualified persons, the luminaries lowest point is at least 8 fit 6; The unbroken conduit before the last point of support is 12 inches
Name 4 different materials that can support a conduit body.
1; rigid metal conduit, 2; intermediate metal conduit, 3; rigid nonmetallic conduit, 4; electrical metallic tubing
An enclosure that contains no devices or supports no luminaires can be supported by entering raceways when all of the conditions are met, name all of conditions.
1; the enclosure does not exceed 100 cubic inch, 2; the enclosure has threaded entrie, 3; the enclosure is supported by two or more conduits threaded wrench tight into the enclosure, 4; each conduit is secured within 36 inch,
An enclosure that contains devices (other than splicing devices) or supports luminaires, lampholders, or other equipment can be supported by entering raceways when all of the conditions are met neame the conditions
1; the enclosure does not exceed 100 cubic inch, 2; the enclosure has threaded entries, 3; the enclosure is supported by two or more conduits, threaded wrench tight into the enclosure, 4; each conduit is secured within 18 inch of the enclosure,
An enclosure can be supported by conduits entering on the same side when all of the following conditions are met: name the conditions
1; the enclosure does not exceed 100 cubic inch, 2; the enclosure has threaded entries or identified hubs, 3; the enclosure is supported by two or more conduits threaded wrench tight in to the enclosure, 4; each conduit is secured within 18 inch of the enclosure,
All permitted wiring methods must be secured to the box, unless the exception in what article section has been met
314,17,C
Boxes containing receptacles, located in the floor, must be listed for the specific application in Article __________
314,27,B
____or fewer luminaire wires smaller than ___ A W G and an equipment grounding conductor can be omitted from box fill calculations where they enter a box from a domed luminaire or similar canopy and terminate within that box
4 or fewer luminaire wires smaller than 14 A W G
Boxes used at luminaire or lampholder outlets in a ceiling must be designed for the purpose and shall be required to support a luminaire weighing a minimum of how many pounds
50 pounds, Article 314,27,A,2
A vertically mounted luminaire or lampholder weighing no more than how many pounds?
6 pounds
Nonmetallic-sheathed cable not fastened to the box must be secured within how many inches of the box
8 inches of the box. Article 314,17,C
Raceways Entering Opposite Removable Covers brings what requirement to the dimension of the the box?
A, Where angle pulls are made, the distance between each raceway entry into the box and the opposite wall of the box must be at least six times the trade size of the largest raceway 314,28,A,2, Where no other raceways enter the same wall of the box, no additional raceway diameters are added. B, Where a raceway or cable enters the wall of a box opposite a removable cover, the distance from the entry wall to the cover can be determined by the distance requirements for one wire per terminal found in Table 312,6,A, and Article 314,28,A,2, Exceptio C, The minimum distance between raceways enclosing the same conductor(s) is six times the trade size of the largest raceway
all metal boxes shall be grounded and bonded in accordance with what article in code book?
Article 250
Unless meeting one of the three exceptions, luminaires and equipment shall be mechanically connected to an equipment grounding conductor as specified in article, ____ ,and sized in accordance with article, _____
Articles (250.118/250.122) 250 dot 118 and 250 dot 122
At least ___ inches of free conductor measured from the point in the conduit body where it emerges from its raceway or cable sheath shall be left at each outlet, junction, and switch point
At least 6 inches.
Equipment grounding conductor or equipment bonding jumpers entering a box count as how many conductor?
Counts as One conductor. for example: The three equipment grounding conductors for this box count as one conductor
is support required where the cable is fished between access points, concealed in the finished surface?
No
how do you support conductors on finished wall?
No support is required where the cable is fished between access points, concealed in the finished surface, and where such supporting of the cable is impractical.
does thickness of he installation count as using the volume of the box
No. Conductor insulation is not a factor when determining box fill calculations.
do Pigtails count as part of calculation for box volume?
No. Pigtails are not counted.
Do Raceway fittings, connectors and hubs count as part of the volume of the box?
No. Raceway fittings, connectors and hubs are not counted.
Do Wire connectors count as using the volume of the box ?
No. Wire connectors are not counted
Do External cable connectors count as using the volume of the box ?
No: External cable connectors are not counted.
does The size of the domed cover or canopy count as adding to the volume of the box?
No: The size of the domed cover or canopy is not a factor.
according to article 314,21. how many inches Damaged or incomplete plaster, drywall, or plasterboard surfaces around boxes employing a flush-type cover or faceplate must be repaired so that no gap or open space greater than how many inches surrounds the box or fitting ?
One Eighth of an Inch
Where a junction box contains 4 AWG or larger conductors that are spliced and the box contains only straight pulls, compliance with 314,28,A,1, and ,A,2 is required, how do you calculate the minimum dimension of the box?
Perform both the straight pull calculation and the angle pull calculation and then compare the results, The minimum dimension will be the larger of the two calculations.
The distance between raceway entries enclosing the same conductor shall not be less than how may times the trade size (metric designator) of the largest raceway,? Article,314,28,A,2, provision is applicable even if the raceway entries are on different walls.
Six times
The maximum number of conductors (for sizes 18 AWG through 6 AWG) permitted in various standard size metal boxes is listed in what Table
Table 314,16,A
What Table shows the cubic-inch volume for conductors ? sizes 18 A W G through 6 A W G.
Table 314,16,B
Supporting screws for nonmetallic boxes must be mounted outside of the box, Truth or Faules ? give article number.
Truth, Article 314.43
on the Domed Covers and Canopies what wires don't count?
Two luminaire wires and one equipment ground are not counted
how do you calculate the box dimensions for U Pull—Two Raceways
Use the angle pull method to calculate U pulls. A box with conduit entries only on one wall has a minimum distance to the opposite wall. Multiply the largest raceway by six and add the sum of the trade size (metric designator) of the other raceway(s) entering the same wall, Article 314,28,A,2, Also, The distance between raceways enclosing the same conductor(s) must be at least six times the trade size of the largest raceway, Article, 314,28,A,2
If multiple rows of raceways enter a box, how do you calculate the box dimensions?
Use the single row that provides the maximum distance, Create an imaginary divider line separating each row, then Perform each row calculation as if in a separate box, Article 314,28,A,2
does conductor that passes through the box without splice, termination or unbroken. count as using the volume of the box ?
Yes: A conductor that passes through the box without splice or termination and its unbroken, counts as one conductor.
Do Luminaire studs count as using the volume of the box ?
Yes: Luminaire studs shall be counted as one conductor. If conductors of different sizes are present in the box, each one shall be counted as the largest conductor
Do the Two internal cable clamps count as using the volume of the box ?
Yes: Two internal cable clamps count as one conductor. Where more than one size conductor is present in the box, the clamp shall be counted as volume of the largest conductor.
Boxes employing a flush-type cover or faceplate in walls or ceilings constructed of combustible material, such as wood shall be flushed ?
Yes: or extend beyond the finished surface
how do you combined volume of a box and plaster
add the CU. IN of plaster to a box. for example. box of 21 CU. IN + plaster of 7 CU. IN = 28 CU. IN
Name the conductors that are not counted on the volume of the box.
conductors that are not leaving the box, such as equipment bonding jumpers and pigtails are not counted on the volume of the box.
what does omitted means?
delete; skip over; neglect
Boxes or conduit bodies containing straight pulls are sized according to the largest raceway, entering the box. The length must be at least how many times the trade size of the largest raceway?, No extra space is required for additional raceways when calculating the minimum length of straight pulls. However, additional space is needed for the width of additional raceways, including locknuts and bushings
eight times
The maximum number of conductors applies only if the box does not contain any_______.
fittings or devices.
Volume does not have to be marked on______what? listed in Table 314.16.A
metal boxes
How many inches of horizontal separation usually required between boxes on opposite sides of the wall.
minimum 24-in.
Volume of the boxes can be increased by using what?
plaster or mud rings, domed covers, extension rings, or similar items
what Section is used to determine the box size requirements for 4 AWG and larger conductors under 600 volts?
section 314,28
The exception pertaining to nonmetallic-sheathed cable entering a box which has no means of securing the cable to the box applies only to what boxes?
single-gang nonmetallic boxes. Article 314,17,C
Where splices or where angle or U pulls are made, the distance between each raceway entry into the box and the opposite wall must be at least how many times the trade size? of the largest raceway in a row. This distance is increased for additional raceway entries in the same row on the same wall of the box by What? Article 314,28,A,2
six times, the sum of the diameters of all other raceway entries
when installing receptacles on covers they must be supported by what ?
the must be supported by more than one screw, unless the box cover or device assembly is listed and identified as single-screw
It is permissible to use the volume marked on a metal box even if it is more than it shown in Table 314.16.A for the same size box. Truth or False
truth: it is permissible.
Are Splices, taps, or devices permitted inside conduit bodies?
yes, if the manufacturer durably and legibly marked the cubic inch capacity on the conduit body Article 314,16,C,2
Boxes employing a flush-type cover or faceplate in walls, or ceilings, constructed of noncombustible material, such as concrete, tile, etc. shall be installed so that the front edge of the box is within how many inches of the finished surface
¼
