Running Conduit to Junction Boxes

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elec_mech

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Virginia, U.S.A.
Hi Everyone,

My apologies if I get any terminology wrong. My background is in electronics with a brief stint in the electrical layout world.

My company makes rotary frequency converters and we've run into some gotcha's with regards to NEC code. We used to use relatively small junction boxes on units with outdoor enclosures. This made the wiring relatively tight inside. On a new job, we're using much larger boxes which are excellent, but the guy who makes the design read something in our NEC 2014 handbook that the distance between the hole in the box and the distribution block must be x inches long based on wire size. I assume this has something to do with bend radius or similar and that makes sense to me. But then the book says something about the length being measured in a straight line.

Our designer took that literally and put the incoming conduit at the top of the box and expects the customer to run the outgoing conduit at the bottom. Normally not a big deal, but the box is placed between the inside and outside of a weather enclosure so the box has to be about half in and half out of the weather enclosure. We're running a pair of 2.5" conduit to two enclosures (incoming power and outgoing power) on the inside. This only leaves about 3" on the outside (see attached pictures), which won't quite accommodate 2.5" conduit on the bottom. The customer wants to run a pair of 3" conduits.

My question is, is there some requirement in the NEC that specifically states one has to run conduit only parallel to a distribution block? Or put another way, if the NEC states a wire must be, say, 8" inside a box, can the conduit come in from the side or back (90 degrees relative to the distribution block, meaning a bend will be made) so long as the wire is 8" or longer inside the box?

This would either a) allow us to run the conduit from the back of the box and push it out (which also helps us better seal the sides to the weather enclosure) or b) allow the customer to run their larger conduit from the side of the box.

Many thanks in advance.
 

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  • Front Junction Box.jpg
    Front Junction Box.jpg
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  • Top Junction Box.jpg
    Top Junction Box.jpg
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  • Side Junction Box 1.jpg
    Side Junction Box 1.jpg
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  • Side Junction Box 2.jpg
    Side Junction Box 2.jpg
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