Junction boxes in conduit run

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Carultch

Senior Member
Location
Massachusetts
What is the limit in the amount of a "conduit run" before a junction box is required??

Thanks... Can't seem to find it.

The closest requirement you'll find, is the 360 degree rule regarding bends.
The NEC does not contain guidelines for this, regarding length. It is up to the contractor to anticipate this, by their own experience. Possibly with pulling tension calculations per their means and methods.
 

al hildenbrand

Senior Member
Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
Thanks. For some reason I was thinking 100 ft. No wonder I couldn't find it:)
As Dave says: The Code is silent about conduit run length between pull points.

The longest one I've ever seen, in the wild, was in a condo complex, a long multistory with all units facing the Mississippi River (high end condos). The switchgear and all meters were on one end (not centrally located), and I was working in the far end. Four floors of four condo's stacked on top of each other with identical floor plans. . . a laundry clothes dryer "stack", four laundry rooms using a common dryer vent with a roof mounted exhaust motor run by a relay in each dryer that switched "house" metered power for the roof exhaust motor.
That house circuit came first to the laundry I was working in, from the far end of the building, 330 feet away, in half inch EMT! ! ! Two #12 TWs in a run with 330 degrees of bend, near as I could tell. And I had to repull it.
 

cowboyjwc

Moderator
Staff member
Location
Simi Valley, CA
We call those "urban code myths". I believe that the reason everyone thought that the code said 100' was, that's how long fish tapes were for years, before they came out with the 200' ones.
 

ADub

Senior Member
Location
Midwest
Occupation
Estimator/Project Manager
300.19 is as close as you'll come to required enclosures in a conduit run. I'm sure someone mentioned you obviously don't want to make a single run longer than your rope or tape.


Sent from my iPhone using Tapatalk
 

480sparky

Senior Member
Location
Iowegia
Technically, 24,901 miles. That's the circumference of the earth. One trip around would equal 360 degrees of bend.

Have fun pulling wire in.
 

Carultch

Senior Member
Location
Massachusetts
Technically, 24,901 miles. That's the circumference of the earth. One trip around would equal 360 degrees of bend.

Have fun pulling wire in.


NICE ONE, Mr 480!

Although I think the factory length of a wire spool would govern, because splices have to be inside a pull box. Longest I've seen is 2500 ft.
 

Carultch

Senior Member
Location
Massachusetts
Technically, 24,901 miles. That's the circumference of the earth. One trip around would equal 360 degrees of bend.

Have fun pulling wire in.

I vaguely recall a rule of thumb of 40 ft and larger bend radii are considered "gentle" enough to not count in the 360 degree rule. Is this just my imagination?

This is within hand flexibility of PVC conduit, which may put bends in a conduit within an undulating trench per the nature of the construction.
 

al hildenbrand

Senior Member
Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
I vaguely recall a rule of thumb of 40 ft and larger bend radii are considered "gentle" enough to not count in the 360 degree rule. Is this just my imagination?
You may well have been within hearing of someone saying, or "teaching", that. However, there is no Code citation that will limit the distance, and there IS a Code limit of 360 degrees of bend.

Field practice teaches us how to "bend" that. . .
 
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