AnsweredAssumed Answered

NEC Pull box Sizing-Section 314.28

Question asked by gennadiy.begelman on Sep 14, 2017
Latest reply on Oct 12, 2017 by brian.baughman

To Whom It May Concerns,


I am a project manager at a final signal design unit.


Could you share any interpretation information or suggestions for the article 314.28 (Pull Box Sizing). Pull box size defined as 8 x largest conduit diameter. Does it apply to all types of pull boxes/handholes? Are there any exceptions?


The typical MnDOT approved handhole size is 24”. We use to specify 4” conduit under roadways and didn’t have any problems so far. Contractors and maintenance teams seems to be comfortable with 4” conduit and prefer it to 3” conduit. But we have to change it to comply with NEC.


I appreciate any information you might have on the issue.



Gennadiy B. Begelman, P.E.

Signal Design Project Engineer

Traffic Engineering

Metropolitan District

1500 West County Road B-2

Roseville, MN 55113

Office: 651-234-7802