Maxium conduit run between pull boxes, NEC Code

[hl53us]

Could anyone tell me what is the maximum conduit run (length) between pull boxes per NEC code? And what page of the NEC code book its on? I have the 2002 version of the NEC code book.

 

[ryan_618]

There is no code requirement for this, contrary to popular belief.

 

[roger]

There is no maximum length, if you have a means to get a rope or pulling means from one end to the other the length of the rope or pulling means is the only limit.

The issue is not having more than 360 deg of bend between pull points, see any of the conduit articles, 3xx.26

Roger

 

[dwellselectric]

I asked that same question about a year ago. Someone asked me that question at work

 

[don_resqcapt19]

There is also a limit based on the pulling calculations. It does no good to pull on the conductor with so much force that it breaks, or that you crush the inslulation as a result of excessive sidewall pressure when pulling around bends.
Don

 

[jrannis]

For some reason I thought it was 500'.

 

[celtic]

For some reason I thought it was 500'.

If you can produce a code article to support what you think, then we will all know what you thought :smile:

 

[mdshunk]

Functionally, pulling tension calcs and number of bends aside, the limit is often based on several more practical factors:

• length of the pull rope to be used
• amount of space available to payoff the conductors
• amount of space available to re-reel or stack conductors at the next pull point
• amount of labor available to make the pull
• amount and type of equipment available to make the pull

 

[Rockyd]

Air compressor - High CFM? Check.

Bucket of Jetline? Check.

"Stand clear the gear!"

DISTANCE UNLIMITED!

 

[peter d]

There is also a limit based on the pulling calculations. It does no good to pull on the conductor with so much force that it breaks, or that you crush the inslulation as a result of excessive sidewall pressure when pulling around bends.
Don

Mention pulling calculations to the average field electrician, and even the above average electrician, and you will most likely get the "deer in the headlights" response. I'm not saying it's right, but there is widespread ignorance of their importance. When it comes right down to it, the mentality of pulling seems to be "Get er done!"

I had no clue about them before I came here, and then I realized I was probably involved in a few pulls that were...shall we say....a bit over the line of sidewall pressure.

 

[mdshunk]

Air compressor - High CFM? Check.

Bucket of Jetline? Check.

"Stand clear the gear!"

DISTANCE UNLIMITED!

Okay, now your jet line is three miles away. Now what are you going to do? Got three miles of pull rope and a Caterpillar tugger?

 

[Rockyd]

1/4 mile on a super tugger (rated 8000 pound) is the most I've ever had to go for distance in a pipe. Beyond that, I would hope is in cable tray (or a utilidor). Beyond that - string an overhead poleline in!

 

[Rockyd]

Come on Marc...No such thing as an impossible pull....

 

[mdshunk]

Come on Marc...No such thing as an impossible pull....

I guess, but your average electrical contractor doesn't have the Hogg-Davis puller that they use when they string up those pole lines. I'm not sure what the pulling capability on those is, but I'm sure it's in the 10's of thousands of pounds.

 

[frenchelectrican]

MDshunk;

Indeed it is have engouh pulling strengh to move fully loaded 767 aircraft.

one contractor whom he dealt with the POCO system and he told me he set the line tenstion about 15,000 to 25,000 lbs depending on which conductors it pull.

Merci, Marc

 

[Rockyd]

Most oil patch electrical in our neck of the woods is big boys. First hint is that they are self insured. So if they bid it, plan on being prepared to rig it! I'd tell you more, but some stuff is just too much on the edge of reality...

This is the company I'm working for on the latest project...CMSI

 

[e57]

I once watched a several ton POCO truck do a wheelie - at which time they realized they needed a back hoe to finish the job. :grin:

 

[electricalperson]

i like to put a pull box every 100 feet when i run emt. for larger pulls we use helpers backs and a long rope its a little more safer than a puller that can rip arms off

 

[roger]

I have been in on 800' + pulls of 600 kcmil in conduit, and 2,000' runs of 500 kcmil 4 conductor with ground MV cable in cable tray.

We had multiple tuggers rigged for these particular MV pulls.

I have used tuggers, pick up trucks, diggers, line trucks, backhoes, trackhoes, and cranes to make pulls, what ever it takes.

Roger

 

[electricalperson]

I have been in on 800' + pulls of 600 kcmil in conduit, and 2,000' runs of 500 kcmil 4 conductor with ground MV cable in cable tray.

We had multiple tuggers rigged for these particular MV pulls.

I have used tuggers, pick up trucks, diggers, line trucks, backhoes, trackhoes, and cranes to make pulls, what ever it takes.

Roger

sounds like a fun day. long pulls with those large conductors are never easy no matter how many pullers are set up