DPW
Member
- Location
- FT. SMITH, AR
Please explain why a pull box can be smaller whenever there is a splice inside the pullbox than whenever it would be used for a straight through pull box since the splice would take up additional volume.
Example: 2" conduit with wiring going straight through (in & out opposite wall): 2 x 8= 16" (as per 314.28.A.1)
2" conduit with wiring spliced but going straight through (in & out opposite wall): 2 x 6= 12" (as per 314.28.A.2)
'08 code:
314.28 Pull and Junction Boxes and Conduit Bodies.
Boxes and conduit bodies used as pull or junction boxes shall comply with 314.28(A) through (D).
Exception: Terminal housings supplied with motors shall comply with the provisions of 430.12.
(A) Minimum Size. For raceways containing conductors of 4 AWG or larger that are required to be insulated, and for cables containing conductors of 4 AWG or larger, the minimum dimensions of pull or junction boxes installed in a raceway or cable run shall comply with (A)(1) through (A)(3). Where an enclosure dimension is to be calculated based on the diameter of entering raceways, the diameter shall be the metric designator (trade size) expressed in the units of measurement employed.
(1) Straight Pulls. In straight pulls, the length of the box shall not be less than eight times the metric designator (trade size) of the largest raceway.
for example, trade size 2 conduit containing four 4/0 AWG, Type THHW conductors (see Annex C, Table C.8) requires a 16-in.-long pull box (8 ? 2 in. = 16 in.). It should be understood that although 16 in. is the required minimum length, a longer pull box may be desired for maximum ease in handling this size conductor.
(2) Angle or U Pulls, or Splices. Where splices or where angle or U pulls are made, the distance between each raceway entry inside the box and the opposite wall of the box shall not be less than six times the metric designator (trade size) of the largest raceway in a row.
Example: 2" conduit with wiring going straight through (in & out opposite wall): 2 x 8= 16" (as per 314.28.A.1)
2" conduit with wiring spliced but going straight through (in & out opposite wall): 2 x 6= 12" (as per 314.28.A.2)
'08 code:
314.28 Pull and Junction Boxes and Conduit Bodies.
Boxes and conduit bodies used as pull or junction boxes shall comply with 314.28(A) through (D).
Exception: Terminal housings supplied with motors shall comply with the provisions of 430.12.
(A) Minimum Size. For raceways containing conductors of 4 AWG or larger that are required to be insulated, and for cables containing conductors of 4 AWG or larger, the minimum dimensions of pull or junction boxes installed in a raceway or cable run shall comply with (A)(1) through (A)(3). Where an enclosure dimension is to be calculated based on the diameter of entering raceways, the diameter shall be the metric designator (trade size) expressed in the units of measurement employed.
(1) Straight Pulls. In straight pulls, the length of the box shall not be less than eight times the metric designator (trade size) of the largest raceway.
for example, trade size 2 conduit containing four 4/0 AWG, Type THHW conductors (see Annex C, Table C.8) requires a 16-in.-long pull box (8 ? 2 in. = 16 in.). It should be understood that although 16 in. is the required minimum length, a longer pull box may be desired for maximum ease in handling this size conductor.
(2) Angle or U Pulls, or Splices. Where splices or where angle or U pulls are made, the distance between each raceway entry inside the box and the opposite wall of the box shall not be less than six times the metric designator (trade size) of the largest raceway in a row.
