logan92@att.net
Member
- Location
- Round Rock Tx
I was wondering if I ran conduit in a straight trench how long does the run have to be before i need a pull box? I searched the 2011 NEC and couldn't find an article showing me the code
Underground conduit
- Thread starter logan92@att.net
- Start date
- Status
- Location
- Simi Valley, CA
You either need one every hundred feet, two hundred feet or any length you want, if you have a vacume to suck a string through. The othe lengths are based on the lengths of your fish tape.
There is no rule.
Cavie
Senior Member
- Location
- SW Florida
and just how froggy your feeling that day
- Location
- Simi Valley, CA
Strathead
Senior Member
- Location
- Ocala, Florida, USA
- Occupation
- Electrician/Estimator/Project Manager/Superintendent
If it is based on the length of many fish tapes it would be more like 185 feet. Just saying
! One of my pet peeves!- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
You need a slight extra length as it comes from the factory to allow for the length you burn off occasionally pushing it into a live panel.If it is based on the length of many fish tapes it would be more like 185 feet. Just saying
Strathead
Senior Member
- Location
- Ocala, Florida, USA
- Occupation
- Electrician/Estimator/Project Manager/Superintendent
You need a slight extra length as it comes from the factory to allow for the length you burn off occasionally pushing it into a live panel.
I am used to idiots er...apprentices, cutting off 10 feet to use as a wall fish, (I am old enough that I lived before they had the fiberglass rods)
unlimited , you can go 800' with no junction box if you like, not a code violation
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
Now if OP is asking what is practical, he will not find that in the NEC. He could try asking members for their opinion on that question based on their experience. They will probably ask him about size of conduit, type of wire (including how much pull it can take without damage), and conduit fill factor.
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mwm1752
Senior Member
- Location
- Aspen, Colo
Vaccum --- pullstring -- pullrope -- wire lube --- pulley -- 4 wheel drive -- nough said
kingpb
Senior Member
- Location
- SE USA as far as you can go
- Occupation
- Engineer, Registered
Apparently the posters have not heard of wiring pulling tension calculations.
The conduit run can be as long as you want it, provided the maximum pulling tension is not exceeded, which if exceeded will cause permanent damage to the cable.
A qualified cable installer will know how to perform those calculations.
The conduit run can be as long as you want it, provided the maximum pulling tension is not exceeded, which if exceeded will cause permanent damage to the cable.
A qualified cable installer will know how to perform those calculations.
mwm1752
Senior Member
- Location
- Aspen, Colo
Do you know the fomula? Where would one find the calculation method. Sounds like a POCO job
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
For online calculators, try the websites of cable manufacturers like Southwire.
JDBrown
Senior Member
- Location
- California
- Occupation
- Electrical Engineer
This conversation brings back memories...
A couple of years ago we designed a complete remodel of a commercial/industrial building with an existing 4160V service. We had one little section of new 5kV cables being run underground -- it was literally so short of a run that almost the entire thing was made up of two 48" radius elbows. And the Plan Checker made me put the calculations on the drawings. I felt a little bit like I was back in school -- "Show your work!" :rant:
The required pulling tension ended up being less than 250 lbs. -- just a bit less than the maximum allowed pulling tension 8,000 lbs.
Anyway, I used this publication from Okonite.
A couple of years ago we designed a complete remodel of a commercial/industrial building with an existing 4160V service. We had one little section of new 5kV cables being run underground -- it was literally so short of a run that almost the entire thing was made up of two 48" radius elbows. And the Plan Checker made me put the calculations on the drawings. I felt a little bit like I was back in school -- "Show your work!" :rant:
The required pulling tension ended up being less than 250 lbs. -- just a bit less than the maximum allowed pulling tension 8,000 lbs.
Anyway, I used this publication from Okonite.
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