What is the formula used for figuring the amount of pulling force when pulling cables into underground conduit?

I have multiple runs of 2" and 3", all PVC except the upright portions (at one end only) which is steel (90 degree elbows and risers out of the ground). All other elbows in the pull are PVC. The conduit runs all start at an underground vault, then continue out to, at the most, 2 PVC 90's, then to a steel 90, then up to cabinet. The max length will be 300'.

I want to purchase a small tugger, and rope, for pulling these cable (type TC). Most conduits will have only 2 or 3 multi-conductor cables, but one has 8 cables(seven 4-conductor cables and one 12-conductor cable).

Any recommendations on a brand of puller/tugger to purchase?

Rick Miell

Rick:
When it was time to buy a puller, I went for the Greenlee Super Tugger package. Yes, it's big and a little on the heavy side....but I haven't found anything that it can't pull yet.

Longest was 990' of 4x750 CU, 2-90's and a straight shot between. Piece o'cake.

4x600; 4" EMT 22-90-90-22 and 335' five sets was no sweat either.

Did you look in the "Electrical Advertizer", you may consider a "used" or refurb unit, the $$ is good.

John

I'm honestly short on a formula this morning, no doubt one exists...

one simple factor is friction, which i have learned to minimize via the proper sized mouse, dragged both ways with (say a 300' run) a gallon of 77 spoon fed into each end.....

the kcmil introduced (angle of entry aslo considered) slides thru like s**t through a goose...

The company I work for has Greenlee super tuggers and Ultra tuggers along with motorized wire feeding equipment.

All of it is great stuff but big bucks, if you do not see a regular use of this equipment I would look into renting it on an as needed basis.

You can only do one task with this stuff so you better have a lot of pulling to do.

Also this stuff can damage and destroy the cans, enclosures, raceways and of course personal.

I will make the Norm Abram's statement.


"Be sure to read, understand and follow the safety directions that come with the equipment".

Get the right ropes, no stretchy stuff.

On the good side, this stuff works great with lube you will get the wires in.

I have installed four 600 kcmils in 3" EMT 350' through three 90s.

The puller was hitting 7000 lbs at times.



[This message has been edited by iwire (edited 11-23-2003).]

Rick,
There is an online pulling calculator here . Note that the limiting factor is often the sidewall pressure (crushing force) at the bend in the conduit run and not the pulling tension itself.
Don

Might be a little small for you but this one interested me for a bit.....well until I saw the price tag. Still looks tempting from time to time. http://www.maxistools.com/product/pullit3000.php