National Electrical Installation Standards

Standards as High as Your Own

Wednesday, December 6, 2017


Two questions: In article 314 for wires larger than #4, for straight pulls the box is to be 8 times the size of the conduit and for angle pulls the box is to be 6 times the size of the conduit. What about when you use a box that is to only have one conduit going into it? The second question. When you pull wire in a conduit that terminates in a panel when you pull a ground wire do you need to bond the knockouts that are larger than the conduit?

Ernie Briggs



Hey Ernie thanks for your questions. The first one is interesting because it is not typical to install a box with only one raceway entry, the conductors don't go anywhere. If splices are made 6 times the raceway size to the opposite wall is required as stated in 314.28(A)(2). If metal raceways or metal sheathed cables are connected to an enclosure with oversized, concentric or eccentric knockouts and the voltage is above 250 volts to ground, bonding must be provided as stated in 250.97.

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