Should I pull heavy wire through conduit to or from a bend at one end?

Question

I am going to be pulling 4/0 4/0 2/0 service wire in 2-1/2" conduit for 175ft. One end is at the meter coming up out of the ground though a 24" sweep and about 3ft of straight conduit on end. Meter is mounted on a 6x6 post. The other end is at the transformer and is straight with open trench on the last couple feet for access to pull wire. I would be able to pull straight out and up.

Seems to me, to be able to get a good pull on wire, that coming from the straight end at transformer would be the easiest. I would appreciate recommendations from anyone with experience doing similar pulls Which direction should I pull from? Thanks

Answer 1

This is subjective I see opinions of folks that don’t do it often.

Pull the wire the to the bend so it will will be last with all other things being equal.

If you start the wire at the bend the entire pull has the 90 to pull through, if you pull the wire so the bend is at the end you only have the weight of the wire to deal with.

Make sure to have someone pushing (pulling wire off the spools) and pushing while the person at the other end is pulling this is an easy pull in ether direction but less resistance with the bend last.

Answer 2

I would feed at the elbow, less likely for 6 feet of rope to cut into the conduit elbow.

I always use a little pulling lube. It shouldn't take much, most of the friction will be at the elbow. If pulling toward the meter and the lube drags off it's hard to add lube for the last 6', but if pushing into the meter and it starts to drag it's easy to add lube to the friction point.

Pushing into meter it is less likely for the lube to pick up debris from the trench going into conduit and (selfishly) less cleaning of the wire for termination in the meter. You should at least wipe down the utility end, but they will likely just trim off the worst part of it.

If the pull gets tough the helper pushing into the elbow is quite effective, pushing into a conduit not fixed in place, 170' away, might not prove to be much help.

Answer 3

I would feed from the elbow end, assuming you have a helper. Wire that thick is stiff, and then pushing the wire down the elbow a few feet away would be loads easier than pulling through the elbow with 200’ of cable dragging.

And, always use lube.

Answer 4

The question is subjective and probably depends on the nuances of your situation. Here's some general advice. You decide.

Benefits of feeding from the end with the elbow:

• An assistant can help push past the elbow and bend the wire.
• The pull is much easier for the remaining distance.
• You don't have to get through the elbow while dragging the wire all the way.

Benefits of feeding from the straight end:

• It's easy sailing most of the way.
• You'd only need to pull a short length beyond the elbow.
• There will be less wear on the conduit from the pull string.

Answer 5

Ed Beal's pulling advice is as good as advice gets.

The electrician promised to hook up the meter, that was not the same as telling you to pull the wire before the meter is installed and then thread the wires through the meter KO. No electrician would say that. I would definitely install the meter before pulling wire, because not doing so is a blatant code violation.

I realize that's a complication you may not have figured for, but that's why being your own GC is hard.

Expecting the electrician to thread the wires through the KO would not be a thing I would do, unless the electrican told me to. You are just begging for a much bigger complication than you have now. It's hard enough finding an electrician willing to follow behind a DIYer and "turn the last bolts". Don't give them reasons to doubt the arrangement.

It is more difficult to guide the wires around the meter pan contents, but not that much more difficult - the wire needs to be guarded and guided anyway on the feeding end, or pull forces will greatly increase as Ed says.

As far as which direction to pull, you need to have a plan and the necessary equipment, and you need to know you have it. So I will actually go against Ed's advice for several reasons, and advise feeding at the meter and pulling from the flat end. The difficulty is greater but that's my point: the job will start hard and get slightly harder as it progresses, so you will sooner know if you need more help. The other direction is easy most of the run, and the last 6’ is like hitting a wall - suddenly quite hard. Again this advice is for a first time puller; Ed certainly doesn't need it!

Also, since I am advising pulling through an installed meter pan, it's easier to guide in loose wires than pull a taut line.

Also, I would ordinarily want the pull rope to be on the end with the unfinished conduit; it's perfectly legal to assemble conduit over a pull rope :) I would only pull the cable through as the power company instructed because they instructed that.

But I maybe wouldn't do it until after the inspector came and went. Last thing you need is to be caught in the crossfire of a jurisdictional squabble between inspector and Utility.

Also keep in mind site security. Aluminum is cheaper, but it's still worth some money. Don't want to have the power company calling and saying "where's the wire" or "why'd you pull it too far" when vandals or thieves did that.

Answer 6

There's some things to consider about putting wires into conduits.

1: you can't push a wire through a conduit that's longer than the "stiffness length" of the wire. when you push a wire it tends to bunch up. when you pull a wire it straightens out.

2: Bends are a force multiplier they multiply the force needed to pull the wire to the bend by some number

3: lube will reduce the multiplication you get from the bend and the force needed to pull it along the straights

Now your situation:

You have a long horizontal run and a short vertical run.

If you feed the wires from the vertical (meter) end they fall by gravity to the bend so it's mostly multiplying zero by something but you need someone to keep feeding else the friction rapidly increases. A guide or slipper at the feed end may help in feeding the wires as you need to prevent them from getting badly scratched. Pulling horizontally on the ground is much easier than pulling vertically in the air.

Wear gloves when feeding to avoid getting pinched if it suddenly hits an easy spot (or passes a hard spot).

The feeder will need to lift every foot of wire to the height of the inlet and feed it in. If you can support the spool on an elevated axle with will help their task.