It may depends on the conduit and cable size but:
How far can you go and/or how many 90's before a hand hole/pull box is required for pulling wire?
(3)350kcmil for an underground service lateral from a pole to a meter on the side of a building.

352.26 Bends-Number in One Run. There shall not be more than 4 quarter bends, 360 total between pull points.

That is for RNC.........



[This message has been edited by GovtVoltage (edited 09-06-2005).]

The NEC does not limit the distance between pull points.

The only NEC limitation is the 360 degrees of bend.

After that common sense needs to be applied, how far can you pull with out damaging the insulation on the conductor.

As a general rule, I agree with iwire, common sense. Now I thought that I had read that you can run a max of 600' underground between manhole/handhole, but I am starting to think that is a local PoCo regulation, bacuase I can't find it again in the NEC...

The only other limitation I can think besides conductor damage is the pulling method. If you have a 240' fishtape in a 250' run...

I try not to rely on breaking the run at a coupling to pull in a rope of string, it's just not fun! Easier (I think) to set a box as you run the conduit.

VA:
Our utilities limit the length of UG runs; IF they are pulling primaries, or if the secondaries belong to them.

They also have stringent specs for the hand holes/pull boxes which must be followed. Also, large radius sweeps are utility specs.

Basically, PSE&G says ...'two 90's, and keep the rest straight.
PS: That's not an NEC thing.

John

The utility (actually their contractor) is the worst about "pullable" laterals around here. I watched them put one together 20' at a time as they pulled the wire in and there is no way it is ever coming out.
They dropped the wire in the trench and threaded the pipe over it, gluing as they went, sand and all.

I was not there in any official capacity so I could just shake my head.

How about 130 feet with four 90's including the 90 at the pole and at the meter?

130 feet with four 90's sounds doable to me. Just don't plan on doing it by hand.

There are online pulling calculators available, try this one by Gerald Newton
http://www.electrician.com/electa1/ductwirepull.html

Tom

cgw I also agree 130' and four 90s is not a problem. I will say that to do that they better be steel sweeps even if the run is PVC. And as Tom said forget about hand pulling it.

We put in a primary once that was (don't yell at me, we followed Dominion VA drawings) 540' of 6" PVC with 5-90's and 1-45. Some of these guys live by rules than make me want to cry! We tied a pull-string to a 20' piece of dead fishtape and pushed through the conduit as we ran it. Made sure to pull the string line back and forth as we lay conduit. If it gets stuck in a glue joint, GOODBYE!

To top it off, we trenched 48" to lay the primary and three weeks later the site guys dropped 36" of fill on top (before the PoCo pulled the feeders)! They got their lines in no problem, and we all wept for joy.

Is this a "U pull", as you pulling, or laying pipe for POCO to pull. Big differance is some may only allow 2-36" sweep 90's. You pulling you can basicaly do what works for you within the basic guidelines, but if this is for PG&E (Our local POCO - P = Premidonna) it would have to be to thier spec's. (2-Sweep 90's, over-sized conduit, and pull rope.) Yours may require the same, or simular.

That pull calculator is great. Notice that 50 lbs of pushing force at the feed side can reduce the pulling tension by 50-66% !!. Pushing and large radius bends can help assure the wire is not damaged. The Greenlee guy at their last counter day was showing me their new cable feeder. He was pushing that the feeder can reduce the need for manual labor to pull slack on the reels. I mentioned that it would be great to reduce pulling tension on th other side and he "unofficially" agreed.

We have a few of the Greenlee feeders and they are a great labor saving device.