Boxes, Cabinets, Panelboards, and Enclosures Flashcards
A 4in trade size EMT enters one side of a pull box, and a 3in aloong with three 2in trade size EMT runs enter the adjacent side. Every run of EMT contains wires of size 4AWG or larger. The minimum size pull box is:
- Method of minnimum dimensions of an angle pull box is found in 314.28(A)(2)
- The side adjacent must be 6X the diameter of the larghest conduit enetering the side
3.add the diameters of each additional conduit to 6X the largest conduit - Side 1= 6 x 4 = 24in
- Side 2 = 6 x 3 = 18in + 2in + 2in +2in = 24in
6.** 24 x 24in**
A junction box has a type NM-B 8/3 cable with ground entering, and two type NM-B 10/3 cables with ground leaving the box. The miinimum cubic inch capacity permitted for this junction box containing no cable clamps or devices is:
Determine an equivalent conductor count for each size of conductor and multiply by the required minimum cubic inch capacity per conductor given in Table 370.16(B)
The equipment grounding conductors only count as one conductor, but the max size involved.
conductors- 10AWG. 8AWG
Grounds. 0. 1
Conductors 6 3
totals 6 4
6 x 3in = 12 in
4 x 2.5in = 15 in
Total = 27 in
The minimum size metallic device box with cable clamps which is permitted to be used to contain a duplex receptacle with a type NM-B 14-2 w.g. cable entering and leaving is:
A. 3 × 2 × 1½ in. B. 3 × 2 × 2½ in. C. 3 × 2 × 2¾ in. D. 3 × 2 × 3½ in. E. 3 × 2 × 4 in.
3 × 2 × 3½ in. The method for figuring the count for conductors in the box is found in 314.16(B). Using the size 14 AWG conductor count of 8 look up the minimum device box depth in Table 314.16(A).
conductors 4
equipment grounds 1
duplex receptacle 2
cable clamps 1
Total count = 14 AWG- 8
